Enhanced Paging Schemes and Connected-State DRX

ABSTRACT

For paging user devices that are link budget limited (LBL), a base station transmits a special ID that is used by said devices to identify a paging frame and/or a paging occasion. When transmitting a paging message for an LBL device, the base station may use: (a) larger aggregation and larger CFI (than conventionally allowed) and (b) a larger number of resource blocks (than conventionally allowed) for paging payload. If paging messages for LBL devices saturate the paging frame capacity, the base station may allocate a plurality of special IDs. If paging messages for LBL devices and/or other data transfers saturate network capacity, at least a subset of the LBL devices may be directed to enter a connected-state discontinuous reception (DRX) mode, wherein those devices will remain in connected mode and periodically check for resource allocations. Paging payload information may be repeatedly transmitted in successive subframes, to support soft combining.

PRIORITY CLAIM INFORMATION

This application is a continuation of U.S. patent application Ser. No.15/860,410, filed Jan. 2, 2018, titled “Enhanced Paging Schemes andConnected-State DRX”, which is a continuation of U.S. patent applicationSer. No. 14/795,733, filed Jul. 9, 2015, titled “Enhanced Paging Schemesand Connected-State DRX”, now U.S. Pat. No. 9,883,480, which claimsbenefit of priority to U.S. Provisional Application No. 62/023,796,filed Jul. 11, 2014, titled “Enhanced Paging Schemes for Power Savingand Range Improvement in LTE and Connected-State DRX”, by Tarik Tabet,Syed Aon Mujtaba and Moustafa Elsayed; and U.S. Provisional ApplicationNo. 62/039,777, filed Aug. 20, 2014, titled “Enhanced Paging Schemes forPower Saving and Range Improvement in LTE and Connected-State DRX”, byTarik Tabet, Syed Aon Mujtaba and Moustafa Elsayed. All of theabove-identified applications are hereby incorporated by reference intheir entireties as though fully and completely set forth herein.

The claims in the instant application are different than those of theparent application or other related applications. The Applicanttherefore rescinds any disclaimer of claim scope made in the parentapplication or any predecessor application in relation to the instantapplication. The Examiner is therefore advised that any such previousdisclaimer and the cited references that it was made to avoid, may needto be revisited. Further, any disclaimer made in the instant applicationshould not be read into or against the parent application or otherrelated applications.

FIELD

The present application relates to wireless communication, and moreparticularly, to mechanisms for paging user equipment (UE) devices thatare link budget limited and mechanisms for performing discontinuousreception during a connected mode of UE operation.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage.Additionally, there exist numerous different wireless communicationtechnologies and standards. Some examples of wireless communicationstandards include GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE Advanced(LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), IEEE802.11 (WLAN or Wi-Fi), IEEE 802.16 (WiMAX), Bluetooth, etc.

In cellular radio access technologies (RATs) such as LTE, paging is aprocedure used by the network (NW) to inform the user equipment (UE) ofan incoming data/call. A paging message requests the UE to attach to thenetwork, and establish a NAS signaling connection with the network. (NASis an acronym for Non-Access Stratum; The Non-Access Stratum is a set ofprotocols in the Evolved Packet System, used to convey non-radiosignalling between the UE and the Mobility Management Entity for anLTE/E-UTRAN access.) A paging message can also be used to notify the UEof a System Information (SI) change or of ETWS information. (ETWS is anacronym for Earthquake and Tsunami Warning System.)

The network uses the paging procedure mainly because the network doesnot know the location of the UE, e.g., when the UE is in idle mode.Thus, paging is the first procedure performed by the network toestablish a connection with the UE. The use of paging to establish aconnection from the network to the UE is similar to the RACH (RandomAccess Channel) procedure used by the UE to establish a connection withthe network.

Detection of a paging message by the UE is extremely important, as thefailure of a UE to detect a paging message can lead to missed calls orlost data. The UE is particularly vulnerable to missing a paging messageif the UE is link budget limited. For example, a UE may be link budgetlimited if it is equipped with a poorly performing antenna system and/orif the UE is located in area of poor coverage (e.g., in the basement ofa building, or far from the base station). Therefore, there exists aneed for improved paging mechanisms for UE devices that are (or become)link budget limited.

SUMMARY

Embodiments are presented herein of, inter alia, improved paging methodswhich help to alleviate the effects of bad reception of the pagingchannel, and of devices configured to implement the methods.

For paging user equipment (UE) devices that are link budget limited, abase station may transmit a special ID (e.g., as part of SIB2) that isused by said UE devices to compute a paging frame identifier and/or apaging occasion identifier. The special ID may be dedicated for use by(and/or with) link budget limited devices. When transmitting a pagingmessage for a link budget limited device, the base station may (a) uselarger aggregation and a larger CFI (control frame indicator) value(than allowed in current wireless communication standards) for pagingcontrol information, and (b) use a larger number of resource blocks(than allowed in current wireless communication standards) for pagingpayload. The paging occasion identifier may be computed based on adedicated value of parameter Ns and a dedicated set of paging occasionidentifier values (different from conventionally-used paging occasionidentifier values).

If paging messages for link budget limited devices start to saturate thecapacity of the single paging frame determined by the special ID, thebase station may allocate a plurality of special IDs, thus implying aplurality of available paging frames for such devices.

If paging messages for link budget limited devices and/or other datatransfers start to saturate network capacity, at least a subset of thelink budget limited devices may be directed to enter a connected-statediscontinuous reception (DRX) mode, wherein those devices willperiodically check for resource allocations while remaining in connectedmode.

In some embodiments, paging payload information may be initiallytransmitted on a paging occasion, and immediately followed by repeatedtransmissions in the following subframes, to support soft combining atthe user device.

Note that the techniques described herein may be implemented in and/orused with a number of different types of devices, including but notlimited to, base stations, access points, cellular phones, portablemedia players, tablet computers, wearable devices, and various othercomputing devices.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings.

FIG. 1 illustrates an exemplary wireless communication system, accordingto some embodiments.

FIG. 2 illustrates a base station (“BS”, or in the context of LTE, an“eNodeB” or “eNB”) in communication with a wireless device, according tosome embodiments.

FIG. 3 illustrates a block diagram for an exemplary wirelesscommunication system, according to some embodiments.

FIG. 4 illustrates a block diagram for an exemplary base station,according to some embodiments.

FIG. 5 shows PDCCH detection performance according to a prior artimplementation with format 1C, aggregation level (AL) of 8, CFI=3.(PDCCH is an acronym for Physical Downlink Control Channel.)

FIG. 6 shows the PDCCH detection performance according to someembodiments of the presently-disclosed PDCCH paging control information,using format 1C, aggregation level (AL) of 28, and CFI=4.

FIGS. 7 and 8 show the block error rate (BLER) performance according tosome embodiments of the presently-disclosed PDSCH paging payloadinformation.

FIG. 9 illustrates a method for operating a base station to implementpaging based on increased PDCCH aggregation level and increased PDCCHtemporal width, according to some embodiments.

FIG. 10 illustrates a method for operating a user equipment device toreceive paging based on increased PDCCH aggregation level and increasedPDCCH temporal width, according to some embodiments.

FIGS. 11 and 12 illustrate examples of a method for operating a userequipment device to determine a paging frame (PF) identifier based on anew ID when the user equipment device is link budget limited, accordingto some embodiments.

FIGS. 13 and 14 illustrate examples of a method for determining a pagingframe (PF) identifier at a link-budget-limited user equipment devicebased on a selected one of a plurality of new IDs dedicated for use bylink budget limited devices, according to some embodiments.

FIGS. 15 and 16 illustrate examples of a method for determining a pagingoccasion identifier at a UE device based on a new set of paging occasionidentifier values that is dedicated for use by link budget limiteddevices, where the new set is disjoint from the set of paging occasionidentifier values used by conventional UE devices for paging, accordingto some embodiments.

FIG. 17 illustrates a method for operating a UE device in aconnected-state DRX mode, according to some embodiments. (DRX is anacronym for discontinuous reception.)

FIG. 18 illustrates a method for performing paging in a wirelesscommunication system, according to some embodiments.

FIGS. 19a-c illustrate paging occasions respectively for N_(S)=1, 2 and4, according to the prior art.

FIG. 20a illustrates a paging payload repetition scheme for the caseN_(S)=1, according to some embodiments.

FIG. 20b illustrates a paging payload repetition scheme for the caseN_(S)=2, according to some embodiments.

FIG. 20c illustrates a paging payload repetition scheme for the caseN_(S)=4, according to some embodiments.

FIG. 21 illustrates an alternative scheme for paging payload repetition,based on a modified paging occasion table, according to someembodiments.

FIG. 22 illustrates a method for operating a user equipment to performpaging based on repeated transmission of paging payload information,according to some embodiments.

FIG. 23 illustrates a method for operating a user equipment device basedon newly-defined paging occasion identifiers and repeated transmissionsof paging payload information, according to some embodiments.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION Terminology

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which perform wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g., smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless telephone system or radio system.

Processing Element—refers to various elements or combinations ofelements. Processing elements include, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since characteristics of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein may be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 MHz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Band—The term “band” has the full breadth of its ordinary meaning, andat least includes a section of spectrum (e.g., radio frequency spectrum)in which channels are used or set aside for the same purpose.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIG. 1—Wireless Communication System

FIG. 1 illustrates a wireless communication system, according to one setof embodiments. It is noted that FIG. 1 represents one possibility amongmany, and that features of the present disclosure may be implemented inany of various systems, as desired.

As shown, the exemplary wireless communication system includes a basestation 102A which communicates over a transmission medium with one ormore wireless devices 106A, 106B, etc., through 106N. Wireless devicesmay be user devices, which may be referred to herein as “user equipment”(UE) or UE devices.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UE devices 106A through 106N. The base station 102 may also beequipped to communicate with a network 100 (e.g., a core network of acellular service provider, a telecommunication network such as a publicswitched telephone network (PSTN), and/or the Internet, among variouspossibilities). Thus, the base station 102 may facilitate communicationbetween the UE devices 106 and/or between the UE devices 106 and thenetwork 100.

The communication area (or coverage area) of the base station 102 may bereferred to as a “cell.” The base station 102 and the UEs 106 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs) or wireless communicationtechnologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE-Advanced(LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD),Wi-Fi, WiMAX, etc.

Base station 102 and other similar base stations (not shown) operatingaccording to one or more cellular communication technologies may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UE devices 106A-N and similar devicesover a wide geographic area via one or more cellular communicationtechnologies.

Thus, while base station 102 may presently represent a “serving cell”for wireless devices 106A-N as illustrated in FIG. 1, each UE device 106may also be capable of receiving signals from one or more other cells(e.g., cells provided by other base stations), which may be referred toas “neighboring cells”. Such cells may also be capable of facilitatingcommunication between user devices and/or between user devices and thenetwork 100.

Note that at least in some instances a UE device 106 may be capable ofcommunicating using multiple wireless communication technologies. Forexample, a UE device 106 might be configured to communicate using two ormore of GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A, WLAN, Bluetooth, one ormore global navigational satellite systems (GNSS, e.g., GPS or GLONASS),one and/or more mobile television broadcasting standards (e.g., ATSC-M/Hor DVB-H), etc. Other combinations of wireless communicationtechnologies (including more than two wireless communicationtechnologies) are also possible. Likewise, in some instances a UE device106 may be configured to communicate using only a single wirelesscommunication technology.

FIG. 2 illustrates an example of UE device 106 (e.g., one of the devices106A through 106N) in communication with base station 102, according toone set of embodiments. The UE device 106 may have cellularcommunication capability, and as described above, may be a device suchas a mobile phone, a hand-held device, a media player, a computer, alaptop or a tablet, or virtually any type of wireless device.

The UE device 106 may include a processor that is configured to executeprogram instructions stored in memory. The UE device 106 may perform anyof the method embodiments described herein by executing such storedinstructions. Alternatively, or in addition, the UE device 106 mayinclude a programmable hardware element such as an FPGA(field-programmable gate array) that is configured to perform any of themethod embodiments described herein, or any portion of any of the methodembodiments described herein.

In some embodiments, the UE device 106 may be configured to communicateusing any of multiple radio access technologies and/or wirelesscommunication protocols. For example, the UE device 106 may beconfigured to communicate using one or more of GSM, UMTS, CDMA2000, LTE,LTE-A, WLAN, Wi-Fi, WiMAX or GNSS. Other combinations of wirelesscommunication technologies are also possible.

The UE device 106 may include one or more antennas for communicatingusing one or more wireless communication protocols or technologies. Inone embodiment, the UE device 106 might be configured to communicateusing a single shared radio. The shared radio may couple to a singleantenna, or may couple to multiple antennas (e.g., for MIMO) forperforming wireless communications. Alternatively, the UE device 106 mayinclude two or more radios. For example, the UE 106 might include ashared radio for communicating using either of LTE or 1×RTT (or LTE orGSM), and separate radios for communicating using each of Wi-Fi andBluetooth. Other configurations are also possible.

FIG. 3—Example Block Diagram of a UE

FIG. 3 illustrates a block diagram of a UE 106, according to one set ofembodiments. As shown, the UE 106 may include a system on chip (SOC)300, which may include portions for various purposes. For example, asshown, the SOC 300 may include processor(s) 302 which may executeprogram instructions for the UE 106, and display circuitry 304 which mayperform graphics processing and provide display signals to the display340. The processor(s) 302 may also be coupled to memory management unit(MMU) 340, which may be configured to receive addresses from theprocessor(s) 302 and translate those addresses to locations in memory(e.g., memory 306, read only memory (ROM) 350, NAND flash memory 310).The MMU 340 may be configured to perform memory protection and pagetable translation or set up. In some embodiments, the MMU 340 may beincluded as a portion of the processor(s) 302.

The UE 106 may also include other circuits or devices, such as thedisplay circuitry 304, radio 330, connector I/F 320, and/or display 340.

In the embodiment shown, ROM 350 may include a boot loader, which may beexecuted by the processor(s) 302 during boot up or initialization. Asalso shown, the SOC 300 may be coupled to various other circuits of theUE 106. For example, the UE 106 may include various types of memory(e.g., including NAND flash 310), a connector interface 320 (e.g., forcoupling to a computer system), the display 340, and wirelesscommunication circuitry (e.g., for communication using LTE, CDMA2000,Bluetooth, Wi-Fi, GPS, etc.).

The UE device 106 may include at least one antenna, and in someembodiments multiple antennas, for performing wireless communicationwith base stations and/or other devices. For example, the UE device 106may use antenna 335 to perform the wireless communication. As notedabove, the UE may in some embodiments be configured to communicatewirelessly using a plurality of wireless communication standards.

As described herein, the UE 106 may include hardware and softwarecomponents for implementing a method for responding to enhanced pagingaccording to embodiments of this disclosure.

The processor 302 of the UE device 106 may be configured to implementpart or all of the methods described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). In other embodiments, processor 302may be configured as a programmable hardware element, such as an FPGA(Field Programmable Gate Array), or as an ASIC (Application SpecificIntegrated Circuit).

FIG. 4—Base Station

FIG. 4 illustrates an example of a base station 102, according to someembodiments. It is noted that the base station of FIG. 4 is merely oneexample of a possible base station. As shown, the base station 102 mayinclude processor(s) 404 which may execute program instructions for thebase station 102. The processor(s) 404 may also be coupled to memorymanagement unit (MMU) 440, which may be configured to receive addressesfrom the processor(s) 404 and translate those addresses to locations inmemory (e.g., memory 460 and read only memory (ROM) 450) or to othercircuits or devices.

The base station 102 may include at least one network port 470. Thenetwork port 470 may be configured to couple to a telephone network andprovide a plurality of devices, such as UE devices 106, access to thetelephone network as described above.

The network port 470 (or an additional network port) may also oralternatively be configured to couple to a cellular network, e.g., acore network of a cellular service provider. The core network mayprovide mobility related services and/or other services to a pluralityof devices, such as UE devices 106. In some cases, the network port 470may couple to a telephone network via the core network, and/or the corenetwork may provide a telephone network (e.g., among other UE devicesserviced by the cellular service provider).

The base station 102 may include a radio 430, a communication chain 432and at least one antenna 434. The base station may be configured tooperate as a wireless transceiver and may be further configured tocommunicate with UE devices 106 via radio 430, communication chain 432and the at least one antenna 434. Communication chain 432 may be areceive chain, a transmit chain or both. The radio 430 may be configuredto communicate via various RATs, including, but not limited to, GSM,UMTS, LTE, WCDMA, CDMA2000, WiMAX, etc.

The processor(s) 404 of the base station 102 may be configured toimplement part or all of the methods described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium).

Alternatively, the processor 404 may be configured as a programmablehardware element, such as an FPGA (Field Programmable Gate Array), or asan ASIC (Application Specific Integrated Circuit), or a combinationthereof.

In some embodiments, the base station is configured to support OFDMAdownlink communication and SC-FDMA uplink communication with UE devices.(OFDMA is an acronym for Orthogonal Frequency-Division Multiple Access.SC-FDMA is an acronym for Single Carrier-Frequency Division MultipleAccess.) Paging in LTE

LTE uses various channels so that data can be transported across the LTEradio interface. These channels are used to segregate the differenttypes of data and allow them to be transported across the radio accessnetwork in an orderly fashion. The different channels effectivelyprovide interfaces to the higher layers within the LTE protocolstructure, and enable an orderly and defined segregation of the data.

There are three categories or types of LTE data channels as follows.

Physical channels: These are transmission channels that carry user dataand control messages.

Transport channels: The physical layer transport channels offerinformation transfer to Medium Access Control (MAC) and higher layers.

Logical channels: Provide services for the Medium Access Control (MAC)layer within the LTE protocol structure.

LTE defines a number of physical downlink channels to carry informationreceived from the MAC and higher layers. The LTE downlink comprises aPhysical Downlink Shared Channel (PDSCH) and a Physical Downlink ControlChannel (PDCCH). The PDSCH is the channel that carries all user data andall signaling messages. The PDSCH is the main data bearing channel whichis allocated to users on a dynamic and opportunistic basis. The PDCCHcarries the layer one control for the shared channel. Thus, the PDSCH isthe key channel for communicating information to the UE, and the PDCCHcommunicates metadata for the information, e.g., “who” the data is for,“what” data is sent, and “how” the data is sent over the air in thePDSCH.

As mentioned above, paging is a procedure performed by the network toinform the UE of incoming data or an incoming call (mobile terminatedcall). Put more simply, paging is the mechanism used by the network toinform the UE that it has information (e.g., data or a voice call) forthe UE. In most instances the UE is in idle mode when the paging processoccurs. In the idle mode, the UE performs discontinuous reception (DRX).In other words, the UE is in a sleep mode during part of the DRX cycle,and wakes up during another part of the DRX cycle to check if a pagingmessage is being sent to the UE. Thus, the UE is required to spendenergy (from its battery) while in idle mode to periodically monitor thenetwork for paging messages. The UE receives and decodes the content ofthe paging message, and then the UE initiates the appropriate procedure.For example, the page issued by the network to the UE may cause the UEto attach to the network and establish a NAS signaling connection.

The Physical Downlink Shared Channel (PDSCH) is used to transmit pagingpayload information to the UE. The payload information may include theInternational Mobile Subscriber Identity (IMSI) of the UE being targetedby the page and a PS/CS indicator bit that indicates whether the page isfor packet switched transfer or circuit switched transfer. (Inembodiments where the UE supports only LTE, the PS/CS indicator bit maybe omitted from the payload information.) Furthermore, when a pluralityof UEs are being paged, the payload information may include a pluralityof IMSIs and a plurality of corresponding PS/CS indicators bits.

The Physical Downlink Control Channel (PDCCH) is used to transmit pagingcontrol information to the UE. The paging control information mayinclude resource allocation information that specifies the location ofthe paging payload information in the PDSCH. During idle mode, the UEperiodically wakes up and monitors the PDCCH in order to detect thepresence of a paging message.

The base station may use a P-RNTI to scramble at least a portion (e.g.,the CRC) of the paging control information. (P-RNTI is an acronym for“Paging-Radio Network Temporary Identifier”.) The base station transmitsthe paging control information, including the scrambled portion, in thePDCCH. The P-RNTI is a temporary identity used for paging, and is notunique to any particular UE.

When the UE detects the presence of the P-RNTI scrambled portion in thePDCCH, it decodes the paging control information, and uses the pagingcontrol information to decode the PCH (paging channel) in the PDSCH. (Ifthe UE does not detect the presence of the P-RNTI scrambled portion, theUE may return to its sleep state.) The PCH contains the paging payloadinformation. The paging payload information includes the IMSI of thedevice targeted by the page. The UE checks the included IMSI todetermine if it equals the IMSI of the UE. If the included IMSI is thenot the same as the IMSI of the UE, the UE may return to sleep state.(The page was not intended for this UE.) Alternatively, if the includedIMSI is equal to the IMSI of the UE, the UE may initiate a random accessprocedure to connect to the network.

The base station broadcasts system information, and the UE receives thesystem information. The system information includes parameters that areused by the UE to determine the frames and subframes in which the UEwill wake up and look for the paging messages. These parameters may befound in SIB2 (System Information Block 2).

System Information Blocks (SIBs) provide information from the basestation to the UEs about various parameters of both the Access Stratumand Non Access Stratum. The SIBs contain the parameters that are commonfor all the UEs in the same cell, and are traditionally broadcast inwireless technologies such as LTE.

SIB2 includes a default paging cycle Tdef (under pcchConfig:defaultPagingCycle) and a parameter nB. Those parameters are used by aUE to determine an identifier for a paging frame and an identifier for apaging occasion. A paging occasion (PO) is a subframe that may possiblyinclude a paging message. A paging frame is a radio frame that maycontain one or more paging occasions.

LTE has two timing units, these being the System Frame Number (SFN) andthe Subframe Number. SFN is the timing unit in frame scale, and theSubframe Number is the timing unit at the subframe level. Knowledge ofboth the SFN and the Subframe Number allows location of a particularsubframe in the LTE time domain. With respect to discontinuousreception, the paging frame identifier (I_(PF)) and the paging occasionidentifier I_(PO) allow the UE to know the exact timing when the UE isrequired to wake up to check for a paging message.

According to 3GPP Specification TS 36.304, a paging frame (PF) is anyframe whose system frame number SFN satisfies

SFN mod T=(T div N)*(UE_ID mod N),

where T is the DRX cycle of the UE. Any SFN satisfying this equation issaid to be a paging frame identifier I_(PF). Thus, the paging frameoccurs periodically with a period of T radio frames. T is determined bythe minimum of (a) the UE-specific DRX cycle, if a UE-specific DRX cycleis allocated by a higher layer, and (b) the default DRX cyclebroadcasted in SIB2. If a UE-specific DRX cycle has not been configuredby a higher layer, the default value is used. T can be any one of 32,64, 128 or 256.

The parameter nB can be any one of the values 4T, 2T, T, T/2, T/4, T/8,T/16, T/32.

As noted above, this parameter is provided in from SIB2.

The value N is given by N=min(T,nB), i.e., N is the minimum of T and nB.

UE_ID=IMSI mod 1024, where IMSI is in decimal format and stored in theUSIM of the UE. (USIM is an acronym for Universal Subscriber IdentityModule.)

For the paging occasion identifier I_(PO), the 3GPP Specification TS36.304 defines I_(PO) as shown in the table below, where

Ns = max(1, nB/T) i_s = (UE_ID/N) mod Ns.

TABLE Paging Occasion (PO) for FDD Ns I_(PO) for i_s = 0 I_(PO) for i_s= 1 I_(PO) for i_s = 2 I_(PO) for i_s = 3 1 9 n/a n/a n/a 2 4 9 n/a n/a4 0 4 5 9

See also FIGS. 19a-19c for graphical depictions of each row of the abovetable. FIG. 19a shows that the case N_(S)=1 has only one pagingoccasion, occurring at subframe 9, and corresponding to i_s=0. Thenotation P_(i) _(_) _(s)=k underneath a given subframe number indicatesthat the subframe is a paging occasion corresponding i_s=k. FIG. 19bshows that the case N_(S)=2 has two paging occasions, occurringrespectively at subframes numbers 4 and 9. FIG. 19c shows that the caseN_(S)=4 has four paging occasions, occurring respectively at subframesnumbers 0, 4, 5 and 9.

In order for the UE to improve its detection of the paging channel(PCH), the UE should be able to reliably detect the presence of P-RNTIin the PDCCH. Currently, PDCCH format 1A/1C is used for P-RNTI PDCCH.(See 3GPP Specification TS 36.212 for definition of formats 1A and 1C.)The number of OFDM symbols carrying the PDCCH depends on the networkconfiguration as well as the aggregation level. The term “aggregationlevel” refers to the number of Control Channel Elements (CCE) used forPDCCH.

PDCCH Paging Features for Range Extension

In one embodiment, a paging method uses PDCCH format 1C and CFI=4. CFIis the Control Format Indicator, and indicates the number of contiguousOFDM symbols used for carrying the PDCCH at the beginning of eachsubframe. (In the current LTE standard, CFI values 1, 2 and 3 areavailable, and CFI=4 is reserved for future use. We described here a usefor the CFI=4 case.) Thus, setting CFI=4 for a subframe means that 4OFDM symbols are used for the PDCCH allocation.

Format 1C is similar to format 1A but more compact (less bits) in itsinformation content, meaning that the information content can be encodedwith lower coding rate (greater redundancy) in the PDCCH. Also, theaggregation level of the PDCCH may be changed from the maximum of 8specified by current 3GPP specifications to a larger value, e.g., avalue in the range from 9 to 32. (Unless otherwise stated, theexpression, “the range from A to B”, should be interpreted as a rangeinclusive of its endpoints A and B.) In one embodiment, the aggregationlevel is set equal to 28. The aggregation level, also referred to as theCCE aggregation level, is the number of Control Channel Elements (CCEs)in a PDCCH. Each CCE contains 9 Resource Element Groups (REGs), whichare distributed within the PDCCH. It is noted that the aggregation levelof 28 corresponds to 25 Resource Blocks (RBs). In one embodiment, thepaging method may use an aggregation level of 28 and a CFI=4, and thus,the performance of the UE in detecting the presence of P-RNTI in PDCCHformat 1C is improved. However, a wide variety of other combinations ofvalues are possible and contemplated.

FIG. 5 shows the PDCCH detection performance according to a prior artimplementation with format 1C, aggregation level (AL) of 8, CFI=3. Thehorizontal axis is E_(C)/N_(OC) (dB), and the vertical axis is Pm_dsg.Furthermore, the performance of one receive antenna vs. two receiveantennas is shown.

FIG. 6 shows the PDCCH detection performance according to the new PDCCHconfiguration, using format 1C, aggregation level (AL) of 28, and CFI=4(with one receive antenna), according to some embodiments.

New P-RNTI for Link-Budget-Limited UE Devices

In order to simplify the decoding of the PDCCH, a new P-RNTI may beintroduced. Similar to the conventional P-RNTI, this new P-RNTI willindicate the presence of a paging channel. However, the new P-RNTI willbe used only for UEs that are link budget limited. UEs that are not linkbudget limited will use the conventional P-RNTI. Thus, when paging oneor more UEs that are link budget limited, the base station may scrambleat least a portion of the paging control information using the newP-RNTI. However, when paging UEs that are not link budget limited, thebase station may scramble at least a portion of the paging controlinformation using the conventional P-RNTI.

PDSCH Paging Features for Range Extension

In one embodiment, a paging method may use an increased number of PDSCHresource blocks for carrying the Paging Channel (PCH) payload for eachUE, i.e., increased as compared to prior art. For example, the PagingChannel (PCH) payload for each UE may occupy 25 RBs, consistent with theabove-described allocation of 25 RBs per UE in the PDCCH. (A variety ofother RB allocation sizes are possible and contemplated.) While theencoded PCH payload may occupy 25 RBs, the underlying informationcontent of the PCH may be 41 bits, where 40 bits is for the IMSI(International Mobile Subscriber Identity) and 1 bit is for PS/CS(Packet-Switched/Circuit-Switched). Thus, if the UE supports bothpacket-switched and circuit-switched networks, a transport block size(TBS)=56 may be used. However, if the UE only supports LTE, then the 1bit for PS/CS can be dropped, and a Transport Block Size (TBS)=40 may beused.

The above configuration for PCH payload helps to ensure that the codingrate of the payload information content is very low. (The informationcontent occupies a larger set of resource blocks than prior art,allowing a lower coding rate, i.e., more redundancy.) This featureincreases the probability of successful decoding of the payloadinformation content.

FIGS. 7 and 8 show the block error rate (BLER) performance for theabove-described paging method, according to some embodiments. In FIG. 7,the upper curve corresponds to TM2, RB25, TBS=56 and CTC, and the lowercurve corresponds to TM2, RB25, TBS=56 and TBCC. In FIG. 8, the uppercurve corresponds to TM2, RB25, TBS=40 and CTC, and the lower curvecorresponds to TM2, RB25, TBS=40 and TBCC.

PO/PF Configuration

As described above, in order to achieve successful decoding of paging,the paging resources per UE used in PDCCH and PDSCH are increased. Thisincreased usage of resources in PDCCH and PDSCH may cause the PDCCHand/or PDSCH to become saturated, i.e., reach network capacity. Forexample, the PSCCH and/or PDSCH may reach network capacity when multiplelink budget limited UEs are simultaneously being paged. To helpalleviate this difficulty, in one embodiment, a paging method mayoperate to group the link budget limited UEs in a single PF and as fewPOs as possible.

The idle mode DRX cycle for link budget limited UEs may be larger thanthe idle mode DRX cycle typically used in the prior art. In the priorart, the idle mode DRX cycle is typically 1.28 s. In some embodiments,the idle mode DRX cycle for link budget limited UEs is greater than 1.28s, e.g., may be set equal to 2.56 s=2×1.28 s, or 5.12 s=4×1.28 s.

In order to achieve the grouping of paging messages for link budgetlimited UEs under a single PF, in one embodiment a new UE_ID is createdand signaled by the network in SIB2. (SIB2, as defined in the LTEspecifications, does not have this capability. We propose an extensionto the definition of SIB2, to support the signaling of this new UE_ID.)This new UE_ID may be referred to herein as the “Range_UE_ID” todistinguish it from the conventional UE_ID (i.e., the UE_ID determinedfrom the IMSI).

All of the UEs that are link budget limited may use this Range_UE_ID tocompute the paging frame identifier I_(PF). For example, the pagingframe identifier may be computed based on the expression:

I _(PF)=SFN mod T=(T div N)*(Range_UE_ID mod N).

Thus, the Range_UE_ID is a mechanism to group together thelink-budget-limited UE devices so they are constrained to receive theirpaging message in frames consistent with the paging frame identifierI_(PF). In contrast, the non-link-budget-limited UEs use theconventional IMSI-based UE_ID to determine paging frame identifiers, andthus, their paging frames are distributed in time, due to the randomnessof the their IMSI values.

It is assumed here that the UE has already indicated to the network(e.g., during RRC exchange of the UE capability) that the UE is a linkbudget limited device. This information regarding link budget limitedstatus may be retained at the Mobile Management Entity (MME) such as,but not limited to, during idle mode.

If the number of link budget limited devices is large and the networkneeds to reserve more than one paging frame for the link budget limiteddevices, then the network can broadcast (from the base station) aplurality of Range_UE_IDs in the SIB2. The UE may select one of theRange_UE_IDs based on the conventional UE_ID (i.e., the IMSI-basedUE_ID). For example, in one embodiment, four Range_UE_IDs may beconfigured, and the UE may:

select Range_UE_ID1 if UE_ID < 256; select Range_UE_ID2 if 256 ≤ UE_ID <512; select Range_UE_ID3 if 512 ≤ UE_ID < 768; and select Range_UE_ID4if 768 ≤ UE_ID < 1024.

Since UE_ID=IMSI mod 1024, the UE_ID can only take values from 0 to1023. The selected Range_UE_ID, denoted Range_UE_ID_(SEL), may be usedto compute the paging frame identifier I_(PF) based on the expression:

I _(PF)=SFN mod T=(T div N)*(Range_UE_ID_(SEL) mod N).

The number of Range_UE_IDs and the definition of selection ranges givenabove is meant as an illustrative example. The number of Range_UE_IDsmay equal any value greater than one, and the selection ranges need notbe uniform in width.

In some embodiments, pcch-Config of SIB2 may be extended as follows:

pcch-Config defaultPagingCycle rf128, nB oneT defaultPagingCycleRangerf512, Range_UE_ID 100.However, it should be understood that the specific parameter valuesgiven in this example may be widely varied in different contexts andapplication scenarios.

In some embodiments, the Range_UE_ID (or the plurality of Range_UE_IDs)may be predefined and known to the network and the UEs that are linkbudget limited. Thus, in these embodiments, the base station does notneed to broadcast the Range_UE_ID(s). Each link-budget-limited UE maystore the Range_UE_ID(s) in memory.

Alternative Method for Determination of Paging Occasion

In one embodiment, the table specifying the paging occasion identifierI_(PO) as a function of Ns and i_s is modified in order to cope with thehigh load of link budget limited UEs. In particular, a new row may beadded to this table to support determination of PO for link budgetlimited UEs. If the UE is link budget limited, the UE may use a fixedvalue of Ns (instead of computing Ns from parameter nB and DRX cycle T).For example, in one embodiment N_(S)=6 is reserved for link budgetlimited UEs. The fixed value of Ns may be used to compute i_s accordingto the conventional formula:

i_s=(UE_ID/N)mod Ns.

The computed value of i_s may then be used to select the paging occasionidentifier I_(PO) from a predetermined set of paging occasion identifiervalues. The predetermined set defines the contents of the new row in thepaging occasion table. The predetermined set includes paging occasionidentifier values that are not conventionally used for paging.(According to the LTE specifications, the paging occasion identifiervalues conventionally used for paging are the values 0, 4, 5 and 9.) Forexample, in the case where the fixed value of Ns is 6, the predeterminedset of paging occasion identifier values may be the set {1, 2, 3, 6, 7,8}. Thus, the link budget limited UEs will use different pagingoccasions than UEs that are not link budget limited. If, in addition,paging frame identifier IPE is computed based on the Range_UE_ID, thenthe paging load can be spread across different frames.

While a link budget limited UE may use the new row to determine thepaging occasion identifier I_(PO) as described above, it may use eitherthe conventional UE_ID or the Range_UE_ID to determine the paging frameidentifier I_(PF).

RRC Connected Mode

In another embodiment, in order to avoid the paging performance issue,the UEs that are categorized as link budget limited may always stay inconnected mode, and operate using connected state DRX (C-DRX). (Thus,the link-budget-limited UEs do not need to be paged. They will read thePDCCH in the ON duration of the C-DRX.) The C-DRX cycle used may besimilar to the idle mode DRX (e.g., 1.28 s or 960 ms) in order to savepower. The eNB will toggle the link budget limited UEs between short andlong C-DRX cycle depending on the traffic and the network load. Thenetwork can still use PDCCH to order a RACH command in case the syncwith the UE is lost.

Paging with Increased PDCCH Aggregation and Increased Bandwidth

In one set of embodiments, a method 900 for operating a base station mayinclude the operations shown in FIG. 9. (The method 900 may also includeany subset of the features, elements and embodiments described above.)The method 900 may be performed to provide improved paging performancein a cellular communication system, especially for UE devices that arelink budget limited. The method 900 may be performed by a processingagent of the base station, e.g., by one or more processors executingprogram instructions, by dedicated digital circuitry such as one or moreASICs, by programmable hardware such as one or more FPGAs, or by anycombination of the foregoing.

At 910, the base station may receive information (e.g., a mobileterminating call, or other information) intended for a user equipment(UE) device, e.g., a UE device that is known to be link budget limited.The information may be received from an infrastructure network of awireless service provider or other network operator.

At 915, the base station may transmit paging control information to theUE in a paging control channel, where the paging control channelcomprises two, three or four OFDM (orthogonal frequency-divisionmultiplexing) symbols and an aggregation level in the range from 9 to32.

At 920, the base station may transmit paging payload data to the UEdevice in a paging data channel, where the paging control information inthe paging control channel specifies a location of the paging payloaddata in the paging data channel, where the paging control information isuseable by the UE to locate the paging payload data. The term “location”refers here to a location in time-frequency resource space.

In some embodiments, the paging control channel is carried by PhysicalDownlink Control Channel (PDCCH) having format 1C as defined in 3GPP TS36.212 and 36.213.

In some embodiments, the paging control information is encoded prior toinclusion in the paging control channel, where the paging controlinformation is encoded with lower coding rate than specified in (orimplied by) existing 3GPP standards.

In some embodiments, the paging control channel is carried by physicaldownlink control channel (PDCCH), and the paging data channel is carriedby physical downlink shared channel (PDSCH).

In some embodiments, the paging control information occupies a number ofresource blocks that is in the range from n_(LOWER) to n_(UPPER), wheren_(LOWER) is a value in the range {12, 13, 14, 15, 16}, where n_(UPPER)is a value in the range from 22 to 48. The paging control informationmay include paging control information for all UEs being paged (or allUEs being paged within a PRNTI-specific group, if a plurality of PRNTIsare being used).

In one embodiment, the paging control information occupies a number ofresource blocks that is in the range from 12 to 25, where the number ofresource blocks depends on the aggregation level.

In some embodiments, the number of resource blocks occupied by thepaging control information depends on the aggregation level. Forexample, the number of resource blocks may be an increasing function ofthe aggregation level.

In some embodiments, the paging payload data occupies a number ofresource blocks that is in the range from n_(LOWER) to n_(UPPER), wheren_(LOWER) is a value in the range {12, 13, 14, 15, 16}, where n_(UPPER)is a value in the range from 22 to 48.

In one embodiment, the paging payload data occupies a number of resourceblocks that is in the range from 12 to 25.

In some embodiments, the number of resource blocks occupied by thepaging control information is the same as the number of resource blocksoccupied by the paging payload data.

In some embodiments, the paging payload data is less than or equal to 40bits in length. This may be advantageous in contexts where a transportblock size used to transmit the paging payload data is equal to 40 bits.(In LTE, transport block size is 40 bits.)

In some embodiments, the UE device may be configured to support LTE butnot WCDMA or GSM. In these embodiments, the paging payload data includesan international mobile subscriber identity (IMSI) of the UE, but doesnot include an indicator for selection between packet switched datatransfer and circuit switched data transfer.

In one set of embodiments, a method 1000 for operating a user equipment(UE) device may include the operations shown in FIG. 10. (The method1000 may also include any subset of the features, elements andembodiments described above.) The method 1000 may be performed toprovide improved paging performance in a cellular communication system.The method 1000 may be performed by (and may be especially beneficialfor) a UE device that is link budget limited. The method 1000 may beperformed by a processing agent of the UE device, e.g., by one or moreprocessors executing program instructions, by dedicated digitalcircuitry such as one or more ASICs, by programmable hardware such asone or more FPGAs, or by any combination of the foregoing.

At 1010, the UE device may receive a paging control channel and a pagingdata channel from a base station, e.g., a paging control channel and apaging data channel as variously described above.

At 1015, in response to determining that the paging control channelcontains a paging-specific temporary identity, the UE device may readpaging control information from the paging control channel. The pagingcontrol channel may include two, three or four OFDM (orthogonalfrequency division multiplexing) symbols and have an aggregation levelin the range from 9 to 32. The paging control information in the pagingcontrol channel may specify a location of paging payload data in thepaging data channel.

At 1020, the UE device may determine the location of the paging payloaddata in the paging data channel based on the paging control information.The UE device may decode the paging payload data using the determinedlocation.

At 1025, in response to a determination that the paging payload datacontains information identifying the UE device, the UE device mayperform a random access procedure to connect to a network through thebase station. (Random access procedures are well known in the field ofwireless communication.)

In some embodiments, the paging control channel is a physical downlinkcontrol channel (PDCCH) having format 1C.

In some embodiments, the paging control channel is carried by physicaldownlink control channel (PDCCH) as defined in 3GPP TS 36.211, and thepaging data channel is carried by physical downlink shared channel(PDSCH) as defined in 3GPP TS 36.211.

In some embodiments, the paging control information occupies a number ofresource blocks that is in the range from n_(LOWER) to n_(UPPER), wheren_(LOWER) is a value in the range {12, 13, 14, 15, 16}, where n_(UPPER)is a value in the range from 22 to 48.

In one embodiment, the paging control information occupies a number ofresource blocks that is in the range from 12 to 25, where the number ofresource blocks depends on the aggregation level.

In some embodiments, the number of resource blocks occupied by thepaging control information depends on the aggregation level. Forexample, said number of resource blocks may be an increasing function ofthe aggregation level.

In some embodiments, the paging payload data occupies a number ofresource blocks that is in the range from n_(LOWER) to n_(UPPER), wheren_(LOWER) is a value in the range {12, 13, 14, 15, 16}, where n_(UPPER)is a value in the range from 22 to 48.

In one embodiment, the paging payload data occupies a number of resourceblocks that is in the range from 12 to 25.

In some embodiments, the number of resource blocks occupied by thepaging control information is the same as the number of resource blocksoccupied by the paging payload data.

In some embodiments, the paging payload data is less than or equal to 40bits in length, where a transport block size used to transmit the pagingpayload data is equal to 40 bits.

In some embodiments, the method 1000 may also include the UE devicereceiving a mobile terminating call after having connected to thenetwork.

In one set of embodiments, a base station may be configured to performwireless communication with a wireless UE device as follows. The basestation includes a radio, and a processing agent operatively coupled tothe radio. (The base station may also include any subset of thefeatures, elements and embodiments described above.) The processingagent is configured to: (a) receive a mobile terminating call intendedfor a user equipment (UE) device; (b) transmit paging controlinformation to the UE device in a paging control channel, where thepaging control channel comprises two, three or four OFDM (orthogonalfrequency-division multiplexing) symbols and has an aggregation level inthe range from 9 to 32; and (c) transmit paging payload data to the UEdevice in a paging data channel, where the paging control information inthe paging control channel specifies a location of the paging payloaddata in the paging data channel, where the paging control information isuseable by the UE to locate the paging payload data. The transmissionoperations (b) and (c) may be performed using the radio.

Determine Paging Frame (PF) from a Single New ID for Link-Budget-LimitedUEs

In one set of embodiments, a method 1100 for operating a user equipment(UE) device may include the operations shown in FIG. 11. (The method1100 may also include any subset of the features, elements andembodiments described above.) The method 1100 may be performed toprovide improved paging performance in a cellular communication system.The method 1100 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited. (The status of being link budget limited may varydynamically, or may be a permanent condition.) The method 1100 may beperformed by a processing agent of the UE device, e.g., by one or moreprocessors executing program instructions, by dedicated digitalcircuitry such as one or more ASICs, by programmable hardware such asone or more FPGAs, or by any combination of the foregoing.

At 1110, the UE device may receive system information from a basestation. The system information may include identification information(e.g., the range_UE_ID described above), a discontinuous reception (DRX)cycle and a parameter nB. The DRX cycle indicates the temporal periodaccording to which the UE device is to periodically wake up and checkfor a paging message. The identification information is preferably notunique to the UE device, but is dedicated for use by UE devices that arelink budget limited. (UE devices that are not link budget limited maysimply ignore the identification information.)

At 1115, in response to determining that said UE device is link budgetlimited, the UE device may compute a paging frame identifier using theidentification information, the DRX cycle and the parameter nB. (Theidentification information may take the place typically held by theIMSI-based UE_ID in conventional computations of page frame identifier,e.g., conventional computations as specified in the LTE specifications.)The page frame identifier identifies the frames which are allowed tocarry page messaging. The UE device may determine whether it is linkbudget limited in any of various ways, e.g., by detecting power of thebase station's downlink signal relative to interference signals, bydetecting a downlink error rate, by determining the number of HARQretransmissions in the downlink, or any combination of the foregoing. Insome embodiments, the UE's status of being link budget limited may be bydesign, and thus, the UE device need not perform any determination oflink budget limited status. (Knowledge of that status may be built intothe control mechanism/algorithm of the UE device.)

At 1120, the UE device may perform discontinuous reception using thecomputed paging frame identifier. Discontinuous reception involvesperiodically waking from a low (or lower) power state to check for theoccurrence of a page message directed to the UE device. The page frameidentifier is used to determine the period between successive wake-uptimes, e.g., as variously described above.

In one set of embodiments, a method 1200 for operating a user equipment(UE) device may include the operations shown in FIG. 12. (The method1200 may also include any subset of the features, elements andembodiments described above.) The method 1200 may be performed toprovide improved paging performance in a cellular communication system.The method 1200 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited. (The status of being link budget limited may varydynamically, or may be a permanent condition.)

At 1210, the UE device may receive system information from a basestation, where the system information includes: identificationinformation (e.g., the range_UE_ID described above) that is dedicatedfor use by UE devices that are link budget limited; a discontinuousreception (DRX) cycle; and a parameter nB. (UE devices that are not linkbudget limited may simply ignore the identification information.) Thebase station may broadcast the system information, e.g., as part ofSIB2.

At 1215, in response to determining that said UE device is link budgetlimited, the UE device may compute a paging frame identifier using theidentification information, the DRX cycle and the parameter nB.Furthermore, each of the link-budget-limited UE devices in communicationwith the base station may similarly compute its paging frame identifierbased on the same identification information, with the result that eachlink-budget-limited UE device uses the same value of paging frameidentifier, and wakes up in the same radio frame of the DRX cycle tocheck for paging messages. Thus, for the purpose of paging, thelink-budget-limited UEs are “grouped together” in the same radio frame.The base station may be configured to send paging messages for thelink-budget-limited UE devices only in radio frames consistent with thecommon value of paging frame identifier.

At 1220, in a discontinuous reception (DRX) mode of operation, the UEdevice may: wake from sleep at a particular subframe of a particulardownlink frame transmitted by the base station, where the particulardownlink frame and particular subframe are determined respectively bythe paging frame identifier and a paging occasion identifier; anddetermine if the particular subframe includes paging payload informationtargeted for the UE device. This determination may involve examining thepaging payload information to determine if the IMSI (or more generally,the subscriber identity) of the UE device is included in the pagingpayload information.

At 1225, in response to determining that the particular subframeincludes paging payload information targeted for the UE device, the UEdevice may invoke a random access procedure to establish a connectionbetween the UE device and the base station. Random access procedures arewell known in the field of wireless communication, and thus, need not beexplained here.

In some embodiments, the method 1200 may also include the followingaction. In response to said determining that the UE device is linkbudget limited, the UE device may determining the paging occasionidentifier based on a subscriber identity of the UE device, the DRXcycle and the parameter nB.

In some embodiments, the action of determining the paging occasionidentifier includes: computing a parameter Ns based on the DRX cycle andthe parameter nB, where the parameter Ns represents a number ofavailable paging occasions per paging frame; computing an index i_sbased on the subscriber identity of the UE device, the DRX cycle and theparameter nB, where the index i_s indicates one of the available pagingoccasions; and accessing an identifier value for said one of theavailable paging occasions from a table using the parameter Ns and indexi_s.

In some embodiments, the method 1200 may also include, in response tosaid determining that the UE device is link budget limited, determiningthe paging occasion identifier based on the identification information,the DRX cycle and the parameter nB.

In some embodiments, the action of determining the paging occasionidentifier includes: computing a parameter Ns based on the DRX cycle andthe parameter nB, where the parameter Ns represents a number ofavailable paging occasions per paging frame; computing an index i_sbased on the identification information, the DRX cycle and the parameternB, where the index i_s indicates one of the available paging occasions;and accessing an identifier value for said one of the available pagingoccasions from a table using on the parameter Ns and index i_s.

In some embodiments, the method 1200 may also include, in response tosaid determining that the UE device is link budget limited, determiningthe paging occasion identifier by performing the following operations.(A) The UE device may compute an index i_s based on: a fixed value ofparameter Ns; a subscriber identity of the UE device; the DRX cycle; andthe parameter nB. The fixed value is used by UE devices that are linkbudget limited. The index i_s indicates a paging occasion identifiervalue from a fixed set of available paging occasion identifier values.The fixed set of available paging occasion identifier values is disjointfrom a conventional set of paging occasion identifier values used by UEdevices that are not link budget limited. (The base station transmitspaging to non-link-budget-limited UE devices in the conventionalfashion, using subframes consistent with the conventional set of pagingoccasion identifier values.) (B) The link-budget-limited UE device maythen access said paging occasion identifier value from a table includingat least the fixed set of available paging occasion identifier valuesusing the index i_s.

In some embodiments, the fixed value of parameter Ns is not a member ofthe set {1, 2, 4}. For example, in some embodiments, the fixed value isequal to 6.

In some embodiments, the conventional set of paging occasion identifiervalues is defined by the set of subframe indices {0, 4, 5, 9}.

In some embodiments, the above-described fixed set of available pagingoccasion identifier values is defined by the set of subframe indices {1,2, 3, 6, 7, 8}.

In some embodiments, the number Ns of the available paging occasionidentifier values in said fixed set is greater than or equal to six. Theindex i_s may be computed based in part on the number Ns.

Paging Frame (PF) Determined from One of a Set of New IDs forLink-Budget-Limited UEs

In one set of embodiments, a method 1300 for operating a user equipment(UE) device may include the operations shown in FIG. 13. (The method1300 may also include any subset of the features, elements andembodiments described above.) The method 1300 may be performed toprovide improved paging performance in a cellular communication system.The method 1300 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited. (The status of being link budget limited may varydynamically, or may be a permanent condition.)

At 1310, the UE device may receive system information from a basestation, where the system information includes; one or more of aplurality of identifiers (e.g., the above-described Range_UE_IDs); adiscontinuous reception (DRX) cycle; and a parameter nB. The identifiersare preferably dedicated for use by UE devices that are link budgetlimited, and thus, may be referred to as LBL-paging identifiers. Inother words, the base station transmits (or broadcasts) one or more ofthese identifiers only when paging a UE device(s) that is (are) known tobe link budget limited.

At 1315, in response to determining that said UE device is link budgetlimited, the UE device may: determine a user-specific ID from asubscriber identity of the UE device; select one of the plurality ofidentifiers based on the user-specific ID; and compute a paging frameidentifier using the selected identifier, the DRX cycle and theparameter nB. The user-specific ID may be determined from the subscriberidentity (e.g., IMSI) in a conventional manner. The selection of one ofthe identifiers may be performed according to a mapping (or function)from a set of possible user-specific IDs to the plurality ofidentifiers. The mapping (or function) is known by the base station orthe network infrastructure node(s) responsible for generation of pagingmessages. According to the mapping, different link-budget-limited UEdevices will map to different ones of the identifiers. The base stationis constrained to transmit paging for any given link-budget-limited UEdevice on a radio frame agreeing with the corresponding identifier.Thus, the paging messages for link-budget-limited UE devices are spreadout over a plurality of paging frames. This mechanisms allows a largernumber of link-budget-limited UE devices to be served with pagingmessages than if only a single paging identifier were used for alllink-budget-limited UE device.

At 1320, the UE device may perform discontinuous reception using thecomputed paging frame identifier and the DRX cycle.

In one set of embodiments, a method 1400 for operating a user equipment(UE) device may include the operations shown in FIG. 14. (The method1400 may also include any subset of the features, elements andembodiments described above.) The method 1400 may be performed toprovide improved paging performance in a cellular communication system.The method 1400 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited.

At 1410, the UE device may receive system information from a basestation, where the system information includes a plurality ofidentifiers (Range_UE_IDs), a discontinuous reception (DRX) cycle and aparameter nB, where the identifiers are dedicated for use by UE devicesthat are link budget limited. (The identifiers may simply be ignored byUE device that are not link budget limited.)

At 1415, in response to determining that said UE device is link budgetlimited, the UE device may: determine a user-specific ID from asubscriber identity of the UE device; select one of the plurality ofidentifiers based on the user-specific ID; and compute a paging frameidentifier using the selected identifier, the DRX cycle and theparameter nB.

At 1420, in a discontinuous reception mode of operation, the UE devicemay: wake from sleep at a particular subframe of a particular downlinkframe transmitted by the base station, where the particular downlinkframe and particular subframe are determined respectively by the pagingframe identifier and a paging occasion identifier; and determine if theparticular subframe includes paging payload information targeted for theUE device.

At 1425, in response to determining that the particular subframeincludes paging payload information targeted for the UE device, the UEdevice may invoke a random access procedure to establish a connectionbetween the UE device and the base station.

In some embodiments, the action of selecting one of the plurality ofidentifiers includes: determining which of a plurality of disjointranges the user-specific ID occurs within, where each of the ranges isassociated with a respective one of the identifiers; and selecting theidentifier that corresponds to the determined range.

Determine Paging Occasion (PO) from Modified Ns/i_s Table

In one set of embodiments, a method 1500 for operating a user equipment(UE) device may include the operations shown in FIG. 15. (The method1500 may also include any subset of the features, elements andembodiments described above.) The method 1500 may be performed toprovide improved paging performance in a cellular communication system.The method 1500 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited.

At 1510, the UE device may receive system information from a basestation, where the system information includes at least a discontinuousreception (DRX) cycle and a parameter nB.

At 1515, in response to determining that said UE device is link budgetlimited, the UE device may perform the following operations. (a)Determine a UE identifier based on a subscriber identity of the UEdevice. (b) Compute an index value i_s using: a fixed value of parameterNs; the discontinuous reception (DRX) cycle; the parameter nB; and theUE identifier. (c) Select a paging occasion identifier from a fixed setof available paging occasion identifiers based on the index value i_s.The fixed set of available paging occasion identifiers is disjoint froma conventional set of paging occasion identifiers used by UE devicesthat are not link budget limited. The base station is configured totransmit paging for link-budget-limited UE device on subframesconsistent with the fixed set of paging occasion identifiers, and totransmit paging for non-link-budget-limited UE devices on subframesconsistent with the conventional set of paging occasion identifiers.Thus, the paging for different types of UE device is distributed todifferent sets of subframes. (d) Perform discontinuous reception (DRX)using a paging frame identifier, the DRX cycle and the computed pagingoccasion identifier.

Each UE device that is link budget limited may use the fixed value ofN_(s) while each UE device that is not link budget limited may determinethe value of parameter N_(s) in a conventional fashion (as defined bythe LTE specifications).

In one set of embodiments, a method 1600 for operating a user equipment(UE) device may include the operations shown in FIG. 16. (The method1600 may also include any subset of the features, elements andembodiments described above.) The method 1600 may be performed toprovide improved paging performance in a cellular communication system.The method 1600 may be performed by (and especially beneficial for) a UEdevice that is link budget limited or a UE device that has become linkbudget limited.

At 1610, the UE device may receive system information from a basestation, where the system information includes at least a discontinuousreception (DRX) cycle and a parameter nB.

At 1615, in response to determining that said UE device is link budgetlimited, the UE device may perform the following operations. (a)Determine a UE identifier based on a subscriber identity of the UEdevice. (b) Compute an index value i_s using a fixed value of parameterNs, the discontinuous reception (DRX) cycle, the parameter nB and the UEidentifier. UE devices that are link budget limited may use the fixedvalue of the parameter Ns to compute i_s while UE devices that are notlink budget limited may use the value of N_(S) as defined by existingLTE specifications. (c) Select a paging occasion identifier from a fixedset of available paging occasion identifiers based on the index valueis, where the fixed set of available paging occasion identifiers isdisjoint from a conventional set of paging occasion identifiers used byUE devices that are not link budget limited.

At 1620, in a discontinuous reception (DRX) mode of operation, the UEdevice may: wake from sleep at a particular subframe of a particulardownlink frame transmitted by the base station, where the particulardownlink frame and particular subframe are identified respectively by apaging frame identifier and the paging occasion identifier; anddetermine if the particular subframe includes paging payload informationtargeted for the UE device.

At 1625, in response to determining that the particular subframeincludes paging payload information targeted for the UE device, the UEdevice may invoke a random access procedure to establish a connectionbetween the UE device and the base station.

In some embodiments, the fixed value of Ns is not a member of the set{1, 2, 4}. For example, in some embodiments, the fixed value is equal to6.

In some embodiments, the conventional set of paging occasion identifiersis specified by the set of subframe indices {0, 4, 5, 9}.

In some embodiments, the system information also includes identificationinformation dedicated for use by UEs that are link budget limited, wherethe paging frame identifier is determined based on the identificationinformation, the discontinuous reception (DRX) cycle and the parameternB.

In some embodiments, the paging frame (PO) is determined based on asubscriber identity (e.g., IMSI) of the UE device, the discontinuousreception (DRX) cycle and the parameter nB.

Connected-State DRX Mode

In one set of embodiments, a method 1700 for operating a user equipment(UE) device may include the operations shown in FIG. 17. (The method1700 may also include any subset of the features, elements andembodiments described above.) The method 1700 may be performed by (andespecially beneficial for) a UE device that is link budget limited or aUE device that has become link budget limited.

At 1710, the UE device may establish a connection with a network througha base station, where said establishing causes the UE device to enter aconnected mode of operation. Mechanisms for establishing such asconnection are well known in the field of wireless communication. Insome embodiments, the UE device may establish the connection in a mannerconforming to existing LTE specifications.

At 1715, in response to determining that said UE device is link budgetlimited, the UE device may enter a discontinuous reception (DRX) mode ofoperation while remaining in the connected mode of operation. This modemay be referred to as the C-DRX mode to distinguish it from the idlemode DRX.

The C-DRX mode uses a DRX cycle that repeats periodically, where the DRXcycle includes an ON duration and an OFF duration. The UE device is in asleep mode in the OFF duration. In some embodiments, the C-DRX modeincludes: (a) examining a downlink control channel occurring within theON duration to determine if the downlink control channel includesresource assignment information for the UE device; and (b) in responseto determining that the downlink control channel includes resourceassignment information for the UE device, recovering payload informationfor the UE device from a downlink shared channel using the resourceassignment information. In these embodiments, the UE device is designedso that it does not examine the downlink control channel in the OFFduration, and thus, saves the power and computational effort of decodingthe downlink control channel.

In some embodiments, the method 1700 may also include receiving a DRXcycle value from the base station via RRC signaling, where the DRX cyclevalue determines the period of the DRX cycle. (RRC is an acronym for“Radio Resource Control”.) The DRX cycle value may be changed by thebase station based on an amount of traffic or an amount of network loadexperienced by the base station. (A larger DRX cycle value may be usedwhen traffic or network load is low.)

In some embodiments, the method 1700 may also include receiving a DRXcycle value from the base station via RRC signaling, where the DRX cyclevalue determines the period of the DRX cycle, where an initial DRX cyclevalue (upon initially entering the C-DRX mode) is equal to an idle-modeDRX cycle value (e.g., equal to 1.28 sec or 960 msec).

In one set of embodiments, a method 1800 for operating performing pagingmay include the operations shown in FIG. 18. (The method 1800 may alsoinclude any subset of the features, elements and embodiments describedabove.)

At 1820, a user equipment (UE) 1815 may transmit a message to the basestation 1810, informing the network that the UE is link budget limited.The UE may be link budget limited by design (e.g., by having beenconfigured with a poorly performing antenna system), and/or, bycircumstance (e.g., by being presently located in an area of poor cellcoverage, far from the base station, or hidden from the base station byphysical obstructions). The UE may be configured to automaticallyperform the transmission 1820, e.g., whenever it senses a new basestation. Alternatively, the UE may be configured to perform thetransmission 1820 when it determines that the quality of its receivedsignal from the base station is poor (or weak). For example, the UE maymeasure signal strength (or any other measure of signal quality) of thereceived signal, and perform the transmission 1820 when the measuredvalue falls below a predetermined threshold.

At 1820, the base station broadcasts system information 1825. The systeminformation may include one or more system information blocks (SIBs).The base station may inject a DRX cycle value T, the parameter nB andthe above-described Range_UE_ID in SIB2 (the system information block ofType 2).

At 1830, the UE decodes at least SIB2 from the system information.

At 1832, the UE may compute a paging frame identifier I_(PF) and apaging occasion identifier I_(PO) based on the DRX cycle T, theparameter nB and the Range_UE_ID.

At 1835, the base station transmits a paging message 1840 for thelink-budget-limited UE. The paging message is included in a paging frameand paging occasion consistent with the previously transmitted values ofDRX cycle T, parameter nB and Range_UE_ID.

At 1845, the UE wakes up for every subframe consistent with the computedpaging frame identifier and computed paging occasion identifier, andchecks the PDCCH of the subframe for the presence of P-RNTI.

At 1850, if the UE determines that P-RNTI is present in the PDCCH, theUE decodes resource allocation information from the PDCCH, and checksPDSCH resource block(s) identified by the allocation information, e.g.,PDSCH resource blocks in the same subframe as the PDCCH.

At 1855, if the paging payload within the resource block(s) includesinformation (e.g., IMSI) uniquely identifying the UE, the UE mayinitiate a random access procedure to connect with the network. As iswell known in the art of wireless communication, the random accessprocedure involves sending a physical random access channel (PRACH) 1857to the base station, receiving a random access response 1860, and soforth. As a result of connecting to the network, the UE is able receiveinformation (e.g., a voice call or a packet stream) that caused thepaging message to be sent to the UE.

If the UE determines that the paging payload does not includeinformation uniquely identifying the UE, the UE may return to idle modeuntil the next subframe consistent with the DRX cycle T, the computedpaging frame identifier and the computed paging occasion identifier.

TTI Bundling for Paging in LTE Payload Repetition in SubsequentSubframes

As described in the various embodiments above, in order to achievesuccessful decoding of paging for link-budget-limited UE device, theresources used by PDCCH and PDSCH may be increased. This increase inusage of PDCCH and PDSCH resources may cause the network (NW) capacityfor paging to be reached, e.g., when multiple link budget limiteddevices are being paged simultaneously. In order to alleviate thisimpact, in one embodiment, the base station (e.g., the eNodeB) mayperform paging transmissions as follows.

If Ns=1, then I_(PO)=9. (See the paging occasion table.) In this case,the page load is initially transmitted in subframe I_(PO)=9 of thepaging frame, and the page load is then repeated in a TTI bundling(TTI-B) fashion in sub-frames 0, 1, 2, . . . of the next frame followingthe paging frame, as shown in FIG. 20a , according to some embodiments.(Each of the repetitions is denoted R_(i) _(_) _(s)=0 to provide areminder that it is a repetition of the initial transmissioncorresponding the paging occation P_(i) _(_) _(s)=0.) The repetitionsmay occur in consecutive sub-frames. The number of repetitions may bedetermined by the performance of the UE and/or the load of the network(NW). The page load may contain the IMSIs of all the UEs that needed tobe paged at the current time, i.e., normal devices that handle pagingmessages in a conventional fashion and link budget limited devices thathandle paging messages as variously disclosed herein. (In someembodiments, a UE device may dynamically switch its page handling methodbetween one of the presently-disclosed methods and a conventional methodas its status changes between being link budget limited and not linkbudget limited. The conventional method may be satisfactory when the UEis not link budget limited.)

Even if the normal devices have decoded their page indication from theinitial transmission, the page load may remain the same in therepetitions (i.e., the subsequent transmissions). This will ensure thatthe link budget limited devices are able to soft combine over themultiple transmission instances (i.e, the initial transmission and therepetitions) of the page load.

If Ns=2, then I_(PO) equals either 4 or 9. (See the paging occasiontable.) If I_(PO)=4, the page load is initially transmitted in subframeI_(PO)=4 of the paging frame, and repeated in sub-frames 5, 6, 7, 8 ofthe same paging frame, as shown in FIG. 20b , according to someembodiments. Each of these repetitions is denoted R_(i) _(_) _(s)=0 toprovide a reminder that it is a repetition of the paging occasion P_(i)_(_) _(s)=0 at subframe 4. If I_(PO)=9, the page is initiallytransmitted in subframe I_(PO)=9 of the paging frame, and then repeatedin sub-frames 0, 1, 2, 3 of the next frame following the paging frame,also shown in FIG. 20b , according to some embodiments. Each of theserepetitions is denoted R_(i) _(_) _(s)=1.

If Ns=4, the paging occasion table would allow I_(PO) values 0, 4, 5 and9 corresponding respectively to the values 0, 1, 2 and 3 of variablei_s. (See the paging occasion table.) However, to support paging-payloadrepetition for the link budget limited devices, the paging occasionidentifier values 0 and 5 are more useful than the values 4 and 9. (TheI_(PO) values 0 and 5 each have three immediately following subframesthat are not used for conventional paging. It is beneficial to have thepayload repetitions follow in subframes immediately after the initialpayload transmission.) Thus, the base station and thelink-budget-limited UE device may each access the paging occasion tablewith an index i_s′ that taken from the set {0,2}, and thus, force theselection of either I_(PO)=0 or I_(PO)=5. If i_s′=0, then the pagepayload is initially transmitted in subframe I_(PO)=0 of the pagingframe, and repeated in sub-frames 1, 2, 3, as shown in FIG. 20c ,according to some embodiments. (The initial transmission is denotedP_(i) _(_) _(s′)=0 and each repetition is denoted R_(i) _(_) _(s′)=0.)If i_s′=2, the page payload is initially transmitted in subframeI_(PO)=5, and repeated in sub-frames 6, 7, 8, also shown in FIG. 20c ,according to some embodiments. (The initial transmission is denotedP_(i) _(_) _(s′=2) and each repetition is denoted R_(i) _(_) _(s′=2) Thefollowing formula may be used to compute the index i_s′:

i_s′=2 floor(i_s/2),

where i_s is the index computed according the 3GPP specification TS36.304. The index i_s′ will be used only by the link budget limiteddevices.

Alternative Mechanism Based on Modified Paging Occasion Table

Another proposal to cope with a high load of link budget limited devicesis to change the Ns/i_s table (i.e., the paging occasion table). Themodified table includes a new row containing the I_(PO) values 1 and 6.This new row is dedicated for the paging of link budget limited devices,while the original rows may be used for normal devices (i.e., nonlink-budget-limited devices). The I_(PO) value set {1,6} is advantageousbecause it is disjoint from the set of I_(PO) values conventionally usedfor paging. (The conventionally used set is {0, 4, 5, 9}). Furthermore,within the set of I_(PO) values not used for conventional paging, i.e.,{1,2,3,6,7,8}, the specific choices of 1 and 6 allow maximum space forsubsequently following repetitions.

A link-budget-limited UE selects the I_(PO) value from the set {1,6}based on the Range_UE_ID (or the conventional UE_ID, which is based onthe IMSI of the UE) and the fixed value Ns′=2. (The link budget limitedUE will not need to compute Ns, but simply use the fixed value Ns′=2.)For example, the paging occasion value I_(PO) may be selected based onthe index i_s′ given by:

i_s′ = (Range_UE_ID / N) mod Ns′, or i_s′ = (UE_ID / N) mod Ns′.This will ensure that the link budget limited UEs are using differentpaging occasions than normal devices.

If i_s′=0, then the base station initially transmits the page insubframe I_(PO)=1 of the paging frame, and repeats the transmission ineach of subsequent sub-frames 2 and 3, as shown in FIG. 21, according tosome embodiments.

If i_s′=1, then the base station initially transmits the page insubframe I_(PO)=6 of the paging frame, and repeats the transmission ineach of subsequent sub-frames 7 and 8, as shown in FIG. 21, according tosome embodiments.

If, in addition, the paging frame identifier is computed based on theRange_UE_ID, then it will be possible to group the paging for the linkbudget limited UEs in a separate frame than normal UEs.

In one set of embodiments, a method 2200 for operating a user equipment(UE) device may be performed as shown in FIG. 22. (The method 2200 mayalso include any subset of the features, elements and embodimentsdescribed above.) The method 2200 may be performed by (and especiallybeneficial for) a UE device that is link budget limited or a UE devicethat has become link budget limited. The method 2200 may be performed bya processing agent of the UE device, e.g., by one or more processorsexecuting program instructions, by dedicated digital circuitry such asone or more ASICs, by programmable hardware such as one or more FPGAs,or by any combination of the foregoing.

At 2210, the UE may compute a paging frame identifier and a pagingoccasion identifier based on (a) paging parameters received from a basestation and (b) a subscriber identity of the UE device.

In response to determining (at 2220) that the UE device is link budgetlimited, the UE may perform operations 2230 through 2250. It should benoted that the determining step 2220 may occur in a different order(relative to the other steps) than that depicted in FIG. 22. Forexample, the determining step may be performed immediately prior to thereception of the one or more additional symbol data sets, or perhapsbefore the computation step 2210.

At 2230, the UE may receive an initial symbol data set from a particulardownlink subframe of a particular downlink frame, where the particulardownlink frame and the particular downlink subframe are selected from adownlink signal based on the paging frame identifier and the pagingoccasion identifier. The particular downlink frame is constrained to beconsistent with the paging frame identifier, and the particular downlinksubframe is constrained to be consistent with the paging occasionidentifier. As used herein, the term “symbol data set” is to be broadlyinterpreted as “a plurality of symbols”.

At 2240, the UE may receive one or more additional symbol data setsrespectively from one or more subframes that follow consecutively afterthe particular downlink subframe of the particular downlink frame, wherethe base station has encoded the same paging payload information in theparticular subframe and each of the one or more subframes that followconsecutively after the particular subframe. At 2250, the UE may decodethe paging payload information based on the initial symbol data set andthe one or more additional symbol data sets. The one or more followingsubframes may occur in the particular downlink frame (if there is roomwithin that frame) and/or in the next frame following immediately afterthe particular downlink frame.

In some embodiments, the action of decoding includes soft combining (orharq combining) the initial symbol data set and the one or moreadditional symbol data sets to form a combined symbol data set. Thetechniques of soft combining and harq combining are well understood inthe field of signal processing.

In some embodiments, the action of computing the paging frame identifierand the paging occasion identifier is based on conventional formulasspecified by an existing 3GPP standard (e.g., TS 36.304).

In some embodiments, the paging occasion identifier identifies a lastsubframe of the particular downlink frame, whereupon the one or moreadditional subframes occur in a frame immediately after the particulardownlink frame.

In some embodiments, the paging occasion identifier identifies asubframe of the paging frame, i.e., a subframe whose subframe number istaken from the set {4, 9}.

In some embodiments, the paging occasion identifier is computed based ona formula that forces the paging occasion to be either 0 or 5.

In some embodiments, the formula is

i_s′=2(floor(i_s/2)),

where i_s is computed based on conventional formulas specified by anexisting 3GPP standard (e.g., TS 36.304). The index i_s′ may be used toselect from an N_(S)=4 row of a paging occasion table as defined in theexisting 3GPP standard.

In some embodiments, the base station has used the same encoding schemeto encode the paging payload information in the particular subframe andeach of the one or more subframes that follow consecutively after theparticular subframe.

In some embodiments, the method 2200 may also include initiating arandom access procedure in response to determining that the pagingpayload information indicates that the user device is being paged (e.g.,in response to determining that the paging payload information includesthe IMSI of the UE device).

In one set of embodiments, a user equipment (UE) device may include: atleast one antenna, at least one radio, and a processing agent. (The UEdevice may also include any subset of the features, elements andembodiments described above.) The processing agent may be implemented byone or more processors executing program instructions, by dedicateddigital circuitry such as one or more ASICs, by programmable hardwaresuch as one or more FPGAs, or by any combination of the foregoing. Theat least one radio may be configured to perform cellular communicationusing at least one radio access technology (RAT). The processing agentmay be coupled to the at least one radio. The processing agent and theat least one radio are together configured to perform voice and/or datacommunications with base stations of a wireless network.

The processing agent may be configured to: compute a paging frameidentifier and a paging occasion identifier based on (a) pagingparameters received from a base station and (b) a subscriber identity ofthe UE device.

Furthermore, the processing agent may be configured to performing thefollowing operations in response to determining that the UE device islink budget limited. (1) Receive an initial symbol data set from aparticular downlink subframe of a particular downlink frame, where theparticular downlink frame and the particular downlink subframe areselected from a downlink signal based on the paging frame identifier andthe paging occasion identifier. (2) Receive one or more additionalsymbol data sets respectively from one or more subframes that followconsecutively after the particular downlink subframe of the particulardownlink frame, where the base station has encoded the same pagingpayload information in the particular subframe and each of the one ormore subframes that follow consecutively after the particular subframe.(3) Decode the paging payload information based on the initial symboldata set and the one or more additional symbol data sets.

In various embodiments described herein, a processing agent is referredto as a transmitting to a UE device and/or receiving from a UE device.It is to be understood that those actions of transmission and/orreception are performed by appropriately controlling at least one radioincluding a transmitter and/or a receiver.

In one set of embodiments, a base station may include at least oneantenna, at least one radio, and a processing agent coupled to the atleast one radio. (The base station may also include any subset of thefeatures, elements and embodiments described above.) The processingagent may be configured as variously described above. The at least oneradio may be configured to perform cellular communication using at leastone radio access technology (RAT). The processing agent and the at leastone radio are together configured to perform voice and/or datacommunications with UE devices.

The processing agent may be configured to compute a paging frameidentifier and a paging occasion identifier based on (a) pagingparameters and (b) a subscriber identity of a user equipment (UE)device.

Furthermore, in response to determining (or being informed) that the UEdevice is link budget limited, the processing agent may be configured toperform the following operations. (A) Transmit paging payloadinformation in a particular downlink subframe of a particular downlinkframe, where the particular downlink frame and the particular downlinksubframe are selected from a frame sequence based on the paging frameidentifier and the paging occasion identifier. (B) Transmit the samepaging payload information in each of the one or more subframes thatfollow consecutively after the particular subframe.

In some embodiments, the action of computing the paging frame identifierand the paging occasion identifier is based on conventional formulasspecified by an existing 3GPP standard (e.g., TS 36.304).

In some embodiments, the paging occasion identifier identifies a lastsubframe of the particular downlink frame, whereupon the one or moreadditional subframes occur in a frame immediately after the particulardownlink frame.

In some embodiments, the paging occasion identifier identifies asubframe of the paging frame, i.e., a subframe whose subframe number isselected from the set {4, 9}.

In some embodiments, the paging occasion identifier is computed based ona formula that forces the paging occasion to be either 0 or 5. Forexample, the formula may be given by the expression:

i_s′=2(floor(i_s/2)),

where i_s is computed based on conventional formulas specified by anexisting 3GPP standard (e.g., TS 36.304). The index i_s′ may be used toselect from an N_(S)=4 row (i.e., the row corresponding to N_(S)=4) of apaging occasion table as defined in the existing 3GPP standard.

In some embodiments, the base station uses the same encoding scheme toencode the paging payload information in the particular subframe andeach of the one or more subframe that follow consecutively after theparticular subframe.

In one set of embodiments, a method 2300 for operating a user equipment(UE) device that is link budget limited may be preformed as shown inFIG. 23. (The method 2300 may also include any subset of the features,elements and embodiments described above.) The method 2200 may beperformed by a processing agent of the UE device, e.g., by one or moreprocessors executing program instructions, by dedicated digitalcircuitry such as one or more ASICs, by programmable hardware such asone or more FPGAs, or by any combination of the foregoing.

At 2310, the UE device may receive paging parameters (e.g., parameter nBand the discontinuous reception cycle) from the base station.

At 2320, the UE device may select a paging occasion identifier from afixed set of two paging occasion identifiers (or more generally,N_(FS)>1) based on identification information and the paging parameters.The fixed set is disjoint from the set of paging occasion identifiers{0,4,5,9} conventionally used for paging in LTE.

In some embodiments, the identification information is a classidentifier dedicated for use by UE devices that are link budget limited,where the identification information is received from the base station(e.g., as part of a broadcast of system information). In otherembodiments, the identification information is determined from the IMSIof the UE device, e.g., as variously described above.

At 2330, the UE device may receive an initial symbol data set from aparticular downlink subframe of a particular downlink frame, where theparticular downlink frame and the particular downlink subframe areselected from a downlink signal based on a paging frame identifier andthe paging occasion identifier. (The downlink signal is transmitted bythe base station, and includes a temporal succession of radio frames,with each radio frame including a plurality of subframes.)

At 2340, the UE device may receive one or more additional symbol datasets respectively from one or more subframes that follow consecutivelyafter the particular downlink subframe of the particular downlink frame.The same paging payload information is encoded in the particularsubframe and each of the one or more subframes that follow consecutivelyafter the particular subframe.

At 2350, the UE device may decode the paging payload information basedon the initial symbol data set and the one or more additional symboldata sets.

In some embodiments, the fixed set of available paging occasionidentifiers is the set {1, 6}.

In some embodiments, the action of selecting the paging occasionidentifier includes: computing a selection index i_s′ based on theexpression

i_s′=((identification information)/N)mod Ns′,

where Ns'=2, where N is determined based on the paging parameters; andselecting the paging occasion identifier from the fixed set based on thevalue of the selection index i_s′.

In some embodiments, the paging frame identifier is computed based onthe identification information.

In one set of embodiments, a user equipment (UE) device may include atleast one antenna, at least one radio, and a processing agent coupled tothe at least one radio. (The UE device may also include any subset ofthe features, elements and embodiments described above.) The processingagent may be configured as variously described above. The at least oneradio may be configured to perform cellular communication using at leastone radio access technology (RAT). The processing agent and the at leastone radio are together configured to perform voice and/or datacommunications with base stations of a wireless network.

The processing agent may be configured to receive paging parameters(e.g., parameter nB and the discontinuous reception cycle) from a basestation.

Furthermore, the processing agent may be configured to perform thefollowing operations. (1) Select a paging occasion identifier from afixed set of two paging occasion identifiers based on identificationinformation and the paging parameters, where the fixed set is disjointfrom the set of paging occasion identifiers {0,4,5,9} conventionallyused for paging in LTE. (2) Receive an initial symbol data set from aparticular downlink subframe of a particular downlink frame, where theparticular downlink frame and the particular downlink subframe areselected from a downlink signal based on a paging frame identifier andthe paging occasion identifier. (3) Receive one or more additionalsymbol data sets respectively from one or more subframes that followconsecutively after the particular downlink subframe of the particulardownlink frame, where the base station has encoded the same pagingpayload information in the particular subframe and each of the one ormore subframes that follow consecutively after the particular subframe.(4) Decode the paging payload information based on the initial symboldata set and the one or more additional symbol data sets.

In one set of embodiments, a base station may include at least oneantenna, at least one radio, and a processing agent coupled to the atleast one radio. (The base station may also include any subset of thefeatures, elements and embodiments described above.) The processingagent may be configured as variously described above. The at least oneradio may be configured to perform cellular communication using at leastone radio access technology (RAT). The processing agent and the at leastone radio may be configured to perform voice and/or data communicationswith UE devices.

The processing agent may be configured to transmit paging parameters(e.g., parameter nB and the discontinuous reception cycle) to a userequipment device.

When the UE device is link budget limited, the processing agent may beconfigured to perform the following operations. (1) Select a pagingoccasion identifier from a fixed set of two paging occasion identifiersbased on identification information and the paging parameters, where thefixed set is disjoint from the set of paging occasion identifiers{0,4,5,9} conventionally used for paging in LTE. (2) Transmit pagingpayload information in a particular downlink subframe of a particulardownlink frame, where the particular downlink frame and the particulardownlink subframe are selected from a frame sequence based on a pagingframe identifier and the paging occasion identifier. (3) Transmit thesame paging payload information in each of the one or more subframesthat follow consecutively after the particular subframe.

In some embodiments, the identification information is a classidentifier dedicated for use by UE devices that are link budget limited,whereupon the identification information is transmitted by the basestation (e.g., as part of system information broadcast).

In some embodiments, the identification information is determined fromthe IMSI of the UE device, e.g., an IMSI stored in the UE device.

In some embodiments, the fixed set of available paging occasionidentifiers is the set {1,6}.

In some embodiments, the action of selecting the paging occasionidentifiers includes: computing a selection index i_s′ based on theexpression

i_s′=((identification information)/N)mod Ns′,

where Ns′=2, where N is determined based on the paging parameters; andselecting the paging occasion identifier from the fixed set based on thevalue of the selection index i_s′.

In some embodiments, the paging frame identifier is computed based onthe identification information.

Various additional embodiments are described in the followingparagraphs.

In one set of embodiments, a method for providing improved pagingperformance in a cellular communication system may be performed by abase station. The method may include the following operations.

The base station may receive a mobile terminating call intended for auser equipment (UE) device.

The base station may transmit paging control information to the UE in apaging control channel, wherein the paging control channel comprisestwo, three or four OFDM (Orthogonal Frequency-Division Multiplexing)symbols and an aggregation level in the range from 9 to 32.

The base station may transmit paging payload data to the UE device in apaging data channel. The paging control information in the pagingcontrol channel specifies a location of the paging payload data in thepaging data channel, wherein the paging control information is useableby the UE to locate the paging payload data.

The paging control channel may be a physical downlink control channel(PDCCH) having format 1C.

The paging control information may be encoded prior to inclusion in thepaging control channel, wherein the paging control information isencoded with lower coding rate than specified in existing 3GPPstandards.

In some embodiments, the paging control channel is a physical downlinkcontrol channel (PDCCH); and the paging data channel is a physicaldownlink shared channel (PDSCH).

The paging control information may occupy a number of resource blocksthat is in the range from nLOWER to nUPPER, wherein nLOWER is a value inthe range {12, 13, 14, 15, 16}, wherein nUPPER is a value in the rangefrom 22 to 48.

The number of resource blocks occupied by the paging control informationmay depend on the aggregation level.

The paging payload data may occupy a number of resource blocks that isin the range from nLOWER to nUPPER, wherein nLOWER is a value in therange {12, 13, 14, 15, 16}, wherein nUPPER is a value in the range from22 to 48.

The paging payload data may be less than or equal to 40 bits in length,e.g., when a transport block size used to transmit the paging payloaddata is equal to 40 bits.

In some embodiments, the UE device may support only LTE. In theseembodiments, the paging payload data may include an international mobilesubscriber identity (IMSI) of the UE, but does not include an indicatorfor selection between packet-switched data transfer and circuit-switcheddata transfer.

In one set of embodiments, a method for providing improved pagingperformance in a cellular communication system may be performed by auser equipment (UE) device and include the following operations.

The UE device may receive a paging control channel and a paging datachannel from a base station.

In response to determining that the paging control channel contains apaging-specific temporary identity, the UE device may read pagingcontrol information from the paging control channel, wherein the pagingcontrol channel comprises two, three or four OFDM (orthogonal frequencydivision multiplexing) symbols and has an aggregation level in the rangefrom 9 to 32, wherein the paging control information in the pagingcontrol channel specifies a location of paging payload data in thepaging data channel.

The UE device may determine the location of the paging payload data inthe paging data channel based on the paging control information.

In response to a determination that the paging payload data containsinformation identifying the UE device, the UE device may perform arandom access procedure to connect to a network through the basestation.

In some embodiments, the paging control channel may be a physicaldownlink control channel (PDCCH) having format 1C.

In some embodiments, the paging control channel is a physical downlinkcontrol channel (PDCCH), and the paging data channel is a physicaldownlink shared channel (PDSCH).

In some embodiments, the paging control information may occupy a numberof resource blocks that is in the range from nLOWER to nUPPER, whereinnLOWER is a value in the range {12, 13, 14, 15, 16}, wherein nUPPER is avalue in the range from 22 to 48.

In some embodiments, the number of resource blocks occupied by thepaging control information may depend on the aggregation level.

In some embodiments, the paging payload data may occupy a number ofresource blocks that is in the range from nLOWER to nUPPER, whereinnLOWER is a value in the range {12, 13, 14, 14, 15, 16}, wherein nUPPERis a value in the range from 22 to 48.

In some embodiments, the paging payload data may be less than or equalto 40 bits in length, e.g., when a transport block size used to transmitthe paging payload data is equal to 40 bits.

In some embodiments, the UE device may also receiving a mobileterminating call after having connected to the network.

In one set of embodiments, a base station may be configured to performwireless communication with a wireless device. The base station maycomprise a radio, and a processing agent operatively coupled to theradio. The processing agent may be configured to perform the followingoperations. (1) Receive a mobile terminating call intended for a userequipment (UE) device. (2) Transmit paging control information to the UEin a paging control channel, wherein the paging control channelcomprises two, three or four OFDM (orthogonal frequency-divisionmultiplexing) symbols and an aggregation level in the range from 9 to32. (3) Transmit paging payload data to the UE device in a paging datachannel.

The paging control information in the paging control channel may specifya location of the paging payload data in the paging data channel,wherein the paging control information is useable by the UE device tolocate the paging payload data.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes identification information, adiscontinuous reception (DRX) cycle and a parameter nB.

In response to determining that the UE device is link budget limited,the UE device may compute a paging frame identifier using theidentification information, the DRX cycle and the parameter nB.

The UE device may perform discontinuous reception using the the computedpaging frame identifier.

The identification information may be dedicated for use by UE devicesthat are link budget limited, i.e., used only in connection with thepaging of link-budget-limited UE devices.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes identification information, adiscontinuous reception (DRX) cycle and a parameter nB, wherein theidentification information is dedicated for use by UE devices that arelink budget limited.

In response to determining that the UE device is link budget limited,the UE device may compute a paging frame identifier using theidentification information, the DRX cycle and the parameter nB.

In a discontinuous reception mode of operation, the UE device may: wakefrom sleep at a particular subframe of a particular downlink frametransmitted by the base station, wherein the particular downlink frameand particular subframe are determined respectively by the paging frameidentifier and a paging occasion identifier; and determine if theparticular subframe includes paging payload information targeted for theUE device.

In response to determining that the particular subframe includes pagingpayload information targeted for the UE device, the UE device may invokea random access procedure to establish a connection between the UEdevice and the base station.

In some embodiments, in response to said determining that the UE deviceis link budget limited, the UE device may also determine the pagingoccasion identifier based on a subscriber identity of the UE device, theDRX cycle and the parameter nB.

In some embodiments, the action of determining the paging occasionidentifier may include: (a) computing a parameter Ns based on the DRXcycle and the parameter nB, wherein the parameter Ns represents a numberof available paging occasions; (b) computing an index i_s based on thesubscriber identity of the UE device, the DRX cycle and the parameternB, wherein the index i_s indicates one of the available pagingoccasions; and (c) accessing an identifier value for said one of theavailable paging occasions from a table using the parameter Ns and indexi_s.

In some embodiments, in response to said determining that the UE deviceis link budget limited, the UE device may determine the paging occasionidentifier based on the identification information, the DRX cycle andthe parameter nB.

In some embodiments, the action of determining the paging occasionidentifier includes: (a) computing a parameter Ns based on the DRX cycleand the parameter nB, wherein the parameter Ns represents a number ofavailable paging occasions; (b) computing an index i_s based on theidentification information, the DRX cycle and the parameter nB, whereinthe index i_s indicates one of the available paging occasions; and (c)accessing an identifier value for said one of the available pagingoccasions from a table using on the parameter Ns and index i_s.

In response to said determining that the UE device is link budgetlimited, the UE device may in some embodiments determine the pagingoccasion identifier by: (1) computing an index i_s based on a fixedvalue of parameter Ns, a subscriber identity of the UE device, the DRXcycle and the parameter nB, wherein the fixed value is used by UEdevices that are link budget limited, wherein the index i_s indicates apaging occasion identifier value from a fixed set of available pagingoccasion identifier values, wherein the fixed set of available pagingoccasion identifier values is disjoint from a conventional set of pagingoccasion identifier values used by UE devices that are not link budgetlimited; and (2) accessing said paging occasion identifier value from atable including at least the fixed set of available paging occasionidentifier values using the index i_s.

In some embodiments, the fixed value of parameter Ns is not a member ofthe set {1, 2, 4}.

In some embodiments, the conventional set of paging occasion identifiervalues is defined by the set of subframe indices {0, 4, 5, 9}.

In some embodiments, the fixed set of available paging occasionidentifier values is defined by the set of subframe indices {1, 2, 3, 6,7, 8}.

In some embodiments, a number Ns of the available paging occasionidentifier values in said fixed set is greater than or equal to six. Theindex i_s may be computed based in part on the number Ns.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes a plurality of identifiers, adiscontinuous reception (DRX) cycle and a parameter nB.

In response to determining that the UE device is link budget limited,the UE device may: (a) determine a user-specific ID from a subscriberidentity of the UE device, (b) select one of the plurality ofidentifiers based on the user-specific ID, and (c) compute a pagingframe identifier using the selected identifier, the DRX cycle and theparameter nB.

The UE device may perform discontinuous reception using the computedpaging frame identifier and the DRX cycle.

The identifiers may be dedicated for use by UE devices that are linkbudget limited.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes a plurality of identifiers, adiscontinuous reception (DRX) cycle and a parameter nB, wherein theidentifiers are dedicated for use by UE devices that are link budgetlimited.

In response to determining that said UE device is link budget limited,the UE device may: determine a user-specific ID from a subscriberidentity of the UE device; select one of the plurality of identifiersbased on the user-specific ID; and compute a paging frame identifierusing the selected identifier, the DRX cycle and the parameter nB.

In a discontinuous reception mode of operation, the UE device may: wakefrom sleep at a particular subframe of a particular downlink frametransmitted by the base station, wherein the particular downlink frameand particular subframe are determined respectively by the paging frameidentifier and a paging occasion identifier; and determine if theparticular subframe includes paging payload information targeted for theUE device.

In response to determining that the particular subframe includes pagingpayload information targeted for the UE device, the UE device may invokea random access procedure to establish a connection between the UEdevice and the base station.

In some embodiments, the action of selecting one of the plurality ofidentifiers may include: determining which of a plurality of disjointranges the user-specific ID occurs within, wherein each of the ranges isassociated with a respective one of the identifiers; and selecting theidentifier that corresponds to the determined range.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes at least a discontinuousreception (DRX) cycle and a parameter nB.

In response to determining that the UE device is link budget limited,the UE device may: (a) determine a UE identifier based on a subscriberidentity of the UE device; (b) compute an index value i_s using a fixedvalue of parameter Ns, the discontinuous reception (DRX) cycle, theparameter nB and the UE identifier; and (c) select a paging occasionidentifier from a fixed set of available paging occasion identifiersbased on the index value i_s, wherein the fixed set of available pagingoccasion identifiers is disjoint from a conventional set of pagingoccasion identifiers used by UE devices that are not link budgetlimited.

The UE device may perform discontinuous reception using a paging frameidentifier, the DRX cycle and the computed paging occasion identifier.

In some embodiments, the fixed value of the parameter Ns is used by UEdevices that are link budget limited.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may receive system information from a base station,wherein the system information includes at least a discontinuousreception (DRX) cycle and a parameter nB.

In response to determining that the UE device is link budget limited,the UE device may: (a) determine a UE identifier based on a subscriberidentity of the UE device; (b) compute an index value i_s using a fixedvalue of parameter Ns, the discontinuous reception (DRX) cycle, theparameter nB and the UE identifier, wherein the fixed value of theparameter Ns is used by UE devices that are link budget limited; and (c)select a paging occasion identifier from a fixed set of available pagingoccasion identifiers based on the index value i_s, wherein the fixed setof available paging occasion identifiers is disjoint from a conventionalset of paging occasion identifiers used by UE devices that are not linkbudget limited.

In a discontinuous reception mode of operation, the UE device may: wakefrom sleep at a particular subframe of a particular downlink frametransmitted by the base station, wherein the particular downlink frameand particular subframe are identified respectively by a paging frameidentifier and the paging occasion identifier; and determine if theparticular subframe includes paging payload information targeted for theUE device.

In response to determining that the particular subframe includes pagingpayload information targeted for the UE device, the UE device may invokea random access procedure to establish a connection between the UEdevice and the base station.

In some embodiments, the fixed value of Ns is not a member of the set{1, 2, 4}.

In some embodiments, the conventional set of paging occasion identifiersis specified by the set of subframe indices {0, 4, 5, 9}.

In some embodiments, the system information also includes identificationinformation dedicated for use by UEs that are link budget limited. Inthese embodiments, the paging frame identifier may be determined basedon the identification information, the discontinuous reception (DRX)cycle and the parameter nB.

In some embodiments, the paging frame (PO) may be determined based on asubscriber identity of the UE device, the discontinuous reception (DRX)cycle and the parameter nB.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may establish a connection with a network through a basestation, wherein said establishing causes the UE device to enter aconnected mode of operation.

In response to determining that the UE device is link budget limited,the UE device may enter a discontinuous reception (DRX) mode ofoperation while remaining in the connected mode of operation.

In some embodiments, the DRX mode uses a DRX cycle that repeatsperiodically, where the DRX cycle includes an ON duration and an OFFduration, and where the UE device is in a sleep mode in the OFFduration. In these embodiment, the DRX mode may include: (a) examining adownlink control channel occurring within the ON duration to determineif the downlink control channel includes resource assignment informationfor the UE device; and (b) in response to determining that the downlinkcontrol channel includes resource assignment information for the UEdevice, recovering payload information for the UE device from a downlinkshared channel using the resource assignment information.

In some embodiments, the UE device does not examine the downlink controlchannel in the OFF duration.

In some embodiments, the UE device may also receive a DRX cycle valuefrom the base station via RRC signaling, wherein the DRX cycle valuedetermines the period of the DRX cycle. The DRX cycle value may bechanged by the base station based on an amount of traffic or an amountof network load.

In some embodiments, the UE device may also receive a DRX cycle valuefrom the base station via RRC signaling, wherein the DRX cycle valuedetermines the period of the DRX cycle. The initial DRX cycle value maybe equal to an idle mode DRX cycle.

In one set of embodiments, a method for operating a user equipment (UE)device may include the following operations.

The UE device may compute a paging frame identifier and a pagingoccasion identifier based on (a) paging parameters received from a basestation and (b) a subscriber identity of the UE device.

In response to determining that the UE device is link budget limited,the UE device may: (a) receive an initial symbol data set from aparticular downlink subframe of a particular downlink frame, wherein theparticular downlink frame and the particular downlink subframe areselected from a downlink signal based on the paging frame identifier andthe paging occasion identifier; (b) receive one or more additionalsymbol data sets respectively from one or more subframes that followconsecutively after the particular downlink subframe of the particulardownlink frame, wherein the base station has encoded the same pagingpayload information in the particular subframe and each of the one ormore subframes that follow consecutively after the particular subframe;and (c) decode the paging payload information based on the initialsymbol data set and the one or more additional symbol data sets.

In some embodiments, the action of decoding includes soft combining theinitial symbol data set and the one or more additional symbol data setsto form a combined symbol data set.

In some embodiments, the action of computing the paging frame identifierand the paging occasion identifier is based on conventional formulasspecified by an existing 3GPP standard.

In some embodiments, the paging occasion identifier identifies a lastsubframe of the particular downlink frame, whereupon the one or moreadditional subframes may occur in a frame immediately after theparticular downlink frame.

In some embodiments, the paging occasion identifier identifies asubframe of the paging frame from the set {4, 9}.

In some embodiments, the paging occasion identifier is computed based ona formula that forces the paging occasion to be either 0 or 5.

In some embodiments, the formula is

i_s′=2(floor(i_s/2)),

wherein i_s is computed based on conventional formulas specified by anexisting 3GPP standard. The index i_s′ may be used to select from anN_(S)=4 row of a paging occasion table as defined in the existing 3GPPstandard.

In some embodiments, the base station has used the same encoding schemeto encode the paging payload information in the particular subframe andeach of the one or more subframe that follow consecutively after theparticular subframe.

In some embodiments, the UE device may also initiate a random accessprocedure in response to determining that the paging payload informationindicates that the user device is being paged.

In one set of embodiment, a user equipment (UE) device may be configuredas follows. The UE device may include at least one radio and aprocessing agent. The at least one radio may be configured to performcellular communication using at least one radio access technology (RAT).The processing agent may be coupled to the at least one radio, andconfigured to perform the following operations. (1) Compute a pagingframe identifier and a paging occasion identifier based on (a) pagingparameters received from a base station and (b) a subscriber identity ofthe UE device. (2) In response to determining that the UE device is linkbudget limited, (c) receive an initial symbol data set from a particulardownlink subframe of a particular downlink frame, wherein the particulardownlink frame and the particular downlink subframe are selected from adownlink signal based on the paging frame identifier and the pagingoccasion identifier; (d) receive one or more additional symbol data setsrespectively from one or more subframes that follow consecutively afterthe particular downlink subframe of the particular downlink frame,wherein the base station has encoded the same paging payload informationin the particular subframe and each of the one or more subframes thatfollow consecutively after the particular subframe; and (e) decode thepaging payload information based on the initial symbol data set and theone or more additional symbol data sets.

In some embodiments, said decoding includes soft combining the initialsymbol data set and the one or more additional symbol data sets to forma combined symbol data set.

In some embodiments, said computing the paging frame identifier and thepaging occasion identifier is based on conventional formulas specifiedby an existing 3GPP standard.

In some embodiments, the paging occasion identifier identifies a lastsubframe of the particular downlink frame, wherein the one or moreadditional subframes occur in a frame immediately after the particulardownlink frame.

In some embodiments, the paging occasion identifier identifies asubframe of the paging frame from the set {4, 9}.

In some embodiments, the paging occasion identifier is computed based ona formula that forces the paging occasion to be either 0 or 5.

In some embodiments, the formula is given by:

i_s′=2(floor(i_s/2)),

wherein i_s is computed based on conventional formulas specified by anexisting 3GPP standard. The index i_s′ is used to select from an N_(S)=4row of a paging occasion table as defined in the existing 3GPP standard.

In some embodiments, the base station has used the same encoding schemeto encode the paging payload information in the particular subframe andeach of the one or more subframe that follow consecutively after theparticular subframe.

In one set of embodiments, a base station may be configured as follows.The base station may include at least one radio and a processing agent.The at least one radio is configured to perform cellular communicationusing at least one radio access technology (RAT). The processing agentmay be coupled to the at least one radio, and configured to perform thefollowing operations. (1) Compute a paging frame identifier and a pagingoccasion identifier based on (a) paging parameters and (b) a subscriberidentity of a user equipment (UE) device. In response to determiningthat the UE device is link budget limited: (2) transmit paging payloadinformation in a particular downlink subframe of a particular downlinkframe, wherein the particular downlink frame and the particular downlinksubframe are selected from a frame sequence based on the paging frameidentifier and the paging occasion identifier; and (4) transmit the samepaging payload information in each of the one or more subframes thatfollow consecutively after the particular subframe.

In some embodiments, said computing the paging frame identifier and thepaging occasion identifier is based on conventional formulas specifiedby an existing 3GPP standard.

In some embodiments, the paging occasion identifier identifies a lastsubframe of the particular downlink frame, whereupon the one or moreadditional subframes occur in a frame immediately after the particulardownlink frame.

In some embodiments, the paging occasion identifier identifies asubframe from the set {4, 9}.

In some embodiments, the paging occasion identifier is computed based ona formula that forces the paging occasion to be either 0 or 5.

In some embodiments, the formula is given by:

i_s′(newdevice)=2(floor(i_s/2)),

wherein i_s is computed based on conventional formulas specified by anexisting 3GPP standard. The index i_s′ is used to select from an N_(S)=4row of a paging occasion table as defined in the existing 3GPP standard.

In some embodiments, the base station uses the same encoding scheme toencode the paging payload information in the particular subframe andeach of the one or more subframe that follow consecutively after theparticular subframe.

In one set of embodiments, a method for operating a user equipment (UE)device that is link budget limited may include the following operations.

The UE device may receive paging parameters from the base station.

The UE device may select a paging occasion identifier from a fixed setof two paging occasion identifiers based on identification informationand the paging parameters, wherein the fixed set is disjoint from theset of paging occasion identifiers {0,4,5,9}.

The UE device may receive an initial symbol data set from a particulardownlink subframe of a particular downlink frame, wherein the particulardownlink frame and the particular downlink subframe are selected from adownlink signal based on a paging frame identifier and the pagingoccasion identifier.

The UE device may receive one or more additional symbol data setsrespectively from one or more subframes that follow consecutively afterthe particular downlink subframe of the particular downlink frame,wherein the same paging payload information is encoded in the particularsubframe and each of the one or more subframes that follow consecutivelyafter the particular subframe.

The UE device may decode the paging payload information based on theinitial symbol data set and the one or more additional symbol data sets.

In some embodiments, the identification information is a classidentifier dedicated for use by UE devices that are link budget limited.The identification information may be received from the base station.

In some embodiments, the identification information is determined fromthe IMSI of the UE device.

In some embodiments, the fixed set of available paging occasionidentifiers is the set {1,6}.

In some embodiments, said selecting the paging occasion identifierincludes: computing a selection index i_s′ based on the expression

i_s′=((identification information)/N)mod Ns′,

wherein Ns′=2, wherein N is determined based on the paging parameters;and selecting the paging occasion identifier from the fixed set based onthe value of the selection index i_s′.

In some embodiments, the paging frame identifier is computed based onthe identification information.

In one set of embodiments, a user equipment (UE) device may beconfigured as follows. The UE device may include at least one radio anda processing agent.

The at least one radio is configured to perform cellular communicationusing at least one radio access technology (RAT).

The processing agent may be coupled to the at least one radio, andconfigured to perform the following operations. (1) Receive pagingparameters from the base station. (2) Select a paging occasionidentifier from a fixed set of two paging occasion identifiers based onidentification information and the paging parameters, wherein the fixedset is disjoint from the set of paging occasion identifiers {0,4,5,9}.(3) Receive an initial symbol data set from a particular downlinksubframe of a particular downlink frame, wherein the particular downlinkframe and the particular downlink subframe are selected from a downlinksignal based on a paging frame identifier and the paging occasionidentifier. (4) Receive one or more additional symbol data setsrespectively from one or more subframes that follow consecutively afterthe particular downlink subframe of the particular downlink frame,wherein the base station has encoded the same paging payload informationin the particular subframe and each of the one or more subframes thatfollow consecutively after the particular subframe. (5) Decode thepaging payload information based on the initial symbol data set and theone or more additional symbol data sets.

In one set of embodiments, the identification information is a classidentifier dedicated for use by UE devices that are link budget limited,wherein the identification information is received from the basestation.

In some embodiments, the identification information is determined fromthe IMSI of the UE device.

In some embodiments, the fixed set of available paging occasionidentifiers is the set {1,6}.

In some embodiments, said selecting the paging occasion identifierincludes: computing a selection index i_s′ based on the expression

i_s′=((identification information)/N)mod Ns′,

wherein Ns′=2, wherein N is determined based on the paging parameters;and selecting the paging occasion identifier from the fixed set based onthe value of the selection index i_s′.

In some embodiments, the paging frame identifier is computed based onthe identification information.

In one set of embodiments, a base station may be configured as follows.

The base station may include at least one radio and a processing agent.

The at least one radio is configured to perform cellular communicationusing at least one radio access technology (RAT).

The processing agent may be coupled to the at least one radio, andconfigured to perform the following operations. (1) Transmit pagingparameters to a user equipment (UE). When the UE device is link budgetlimited, (2) select a paging occasion identifier from a fixed set of twopaging occasion identifiers based on identification information and thepaging parameters, wherein the fixed set is disjoint from the set ofpaging occasion identifiers {0,4,5,9}, (3) transmit paging payloadinformation in a particular downlink subframe of a particular downlinkframe, wherein the particular downlink frame and the particular downlinksubframe are selected from a frame sequence based on a paging frameidentifier and the paging occasion identifier, and (4) transmit the samepaging payload information in each of the one or more subframes thatfollow consecutively after the particular subframe.

In some embodiments, the identification information is a classidentifier dedicated for use by UE devices that are link budget limited,wherein the identification information is transmitted by the basestation.

In some embodiments, the identification information is determined fromthe IMSI of the UE device.

In some embodiments, the fixed set of available paging occasionidentifiers is the set {1,6}.

In some embodiments, said selecting the paging occasion identifiersincludes: computing a selection index i_s′ based on the expression

i_s′=((identification information)/N)mod Ns′,

wherein Ns'=2, wherein N is determined based on the paging parameters;and selecting the paging occasion identifier from the fixed set based onthe value of the selection index i_s′.

In some embodiments, the paging frame identifier is computed based onthe identification information.

Embodiments of the present disclosure may be realized in any of variousforms. For example some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106) may be configured toinclude a processor (or a set of processors) and a memory medium, wherethe memory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement amethod, e.g., any of the various method embodiments described herein(or, any combination of the method embodiments described herein, or, anysubset of any of the method embodiments described herein, or, anycombination of such subsets). The device may be realized in any ofvarious forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A user equipment (UE) device, comprising: atleast one radio, wherein the at least one radio is configured to performorthogonal frequency-division multiplexing (OFDM) cellular communicationusing at least one radio access technology (RAT); and a processing agentcoupled to the at least one radio, and configured to: determine that theUE device is a link budget limited UE device based on a measurement ofreceived signal strength from a cell of a network; inform a network thatthe UE device is link budget limited, determine the cell supports anenhanced paging scheme for link budget limited UE devices frominformation received in a system information broadcast message;determine a UE identifier from a subscriber identity of the UE device,determine a range identifier, of a plurality of range identifiers,associated with a range of UE identifier values corresponding to thedetermined UE identifier, wherein the range of UE identifier valuesassociated with the determined range identifier comprises a plurality ofconsecutive UE identifier values in accordance with the enhanced pagingscheme; determine one or more radio frames to monitor for paging controlmessages based on a modulo operation on the determined range identifier;and monitor said one or more or radio frames for paging controlmessages.
 2. The UE device of claim 1, wherein to determine the UEidentifier from the subscriber identity, the processing agent is furtherconfigured to perform a second modulo operation.
 3. The UE device ofclaim 1, wherein the subscriber identity is for an International MobileSubscriber Identity (IMSI).
 4. The UE device of claim 1, whereinnon-link-budget-limited UE devices use SFN mod T=(T div N)*(UE_ID mod N)to determine paging frame identifiers, wherein SFN is a System FrameNumber.
 5. The UE device of claim 1, wherein the range identifier isdetermined based on the information received in the system informationbroadcast message.
 6. The HE device of claim 1, wherein an idle mode DRXcycle for the UE device is configured to be greater than 1.28 seconds.7. The UE device of claim 1, wherein a link budget limited status of theUE device is stored at a mobile management entity (MME) in the network.8. A method for operating a user equipment (UE) device, the methodcomprising: determining that the UE device is a link budget limited UEdevice based on a measurement of received signal strength from a cell ofa network; informing a network that the UE device is link budgetlimited, determining the cell supports an enhanced paging scheme forlink budget limited UE devices from information received in a systeminformation broadcast message; determining a UE identifier from asubscriber identity of the UE device, determining a range identifier, ofa plurality of range identifiers, associated with a range of UEidentifier values corresponding to the determined UE identifier, whereinthe range of UE identifier values associated with the determined rangeidentifier comprise a plurality of consecutive UE identifier values inaccordance with the enhanced paging scheme; determining one or moreradio frames to monitor for paging control messages based on a modulooperation on the determined range identifier; and monitoring said one ormore or radio frames for paging control messages.
 9. The method of claim8, wherein to determine the UE identifier from the subscriber identity,the processing agent is further configured to perform a second modulooperation.
 10. The method of claim 8, wherein the subscriber identity isfor an International Mobile Subscriber Identity (IMSI).
 11. The methodof claim 8, wherein non-link-budget-limited UE devices use SFN mod T=(Tdiv N)*(UE_ID mod N) to determine paging frame identifiers, wherein SFNis a System Frame Number.
 12. The method of claim 8, wherein the rangeidentifier is determined based on the information received in the systeminformation broadcast message.
 13. The method of claim 8, wherein anidle mode DRX cycle for the UE device is configured to be greater than1.28 seconds.
 14. The method of claim 8, wherein a link budget limitedstatus of the UE device is stored at a mobile management entity (MME) inthe network.
 15. A non-transitory computer accessible memory medium,comprising program instructions for a wireless user equipment (UE)device that, when executed by the UE device, cause the UE to: determinethat the UE device is a link budget limited UE device based on ameasurement of received signal strength from a cell of a network; informa network that the UE device is link budget limited, determine the cellsupports an enhanced paging scheme for link budget limited UE devicesfrom information received in a system information broadcast message;determine a UE identifier from a subscriber identity of the UE device,determine a range identifier, of a plurality of range identifiers,associated with a range of UE identifier values corresponding to thedetermined UE identifier, wherein the range of UE identifier valuesassociated with the determined range identifier comprise a plurality ofconsecutive UE identifier values in accordance with the enhanced pagingscheme; determine one or more radio frames to monitor for paging controlmessages based on a modulo operation on the determined range identifier;and monitor said one or more or radio frames for paging controlmessages.
 16. The non-transitory computer accessible memory medium ofclaim 15, wherein to determine the LE identifier from the subscriberidentity, the processing agent is further configured to perform a secondmodulo operation.
 17. The non-transitory computer accessible memorymedium of claim 15, wherein the subscriber identity is for anInternational Mobile Subscriber Identity (IMSI).
 18. The non-transitorycomputer accessible memory medium of claim 15, whereinnon-link-budget-limited UE devices use SFN mod T=(T div N)*(UE_ID mod N)to determine paging frame identifiers, wherein SFN is a System FrameNumber.
 19. The non-transitory computer accessible memory medium ofclaim 15, wherein the range identifier is determined based on theinformation received in the system information broadcast message. 20.The non-transitory computer accessible memory medium of claim 15,wherein an idle mode DRX cycle for the UE device is configured to begreater than 1.28 seconds.